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China was one of the first countries to use coal; as early as before Christ, it was used to smelt copper ore and produce ceramics, and by the Ming dynasty, coke was already being used for iron smelting. However, the use of coal as a raw material for the chemical industry and the gradual development of an industrial system occurred after the Modern Industrial Revolution. The basic structural unit of organic matter in coal is a macromolecule with an aromatic fused ring at its core, surrounded by heterocycles and various functional groups (see coal chemistry). This specific molecular structure enables it to yield solid products such as coke or semi-coke through thermal and catalytic processing under air-free conditions. At the same time, large amounts of gas (including syngas) can be obtained, as well as chemicals and liquid fuels of economic value (such as hydrocarbons, alcohols, ammonia, benzene, toluene, xylene, naphthalene, phenols, pyridines, anthracenes, phenanthrenes, carbazoles, etc.). Therefore, the development of coal chemical industry encompasses two important aspects: energy production and chemical production, which complement each other and promote the advancement of technologies for the comprehensive utilization of coal. In its early stages, it was mainly engaged in the production of metallurgical coke and gas. In the mid-18th century, due to the progress of the Industrial Revolution, Britain’s demand for coke for iron production increased significantly, leading to the invention of coke ovens. In 1763, the honeycomb coke oven, which uses coal for coking, was developed (Figure 1). It consists of an arched chamber made of refractory bricks, with coal and air inlets provided at the top and side walls respectively. After ignition, the volatile components released from the decomposition of the coal burn together with the air that enters through the side doors in the arch-shaped chamber. The heat generated is radiated from the ceiling to the coal layer, providing the heat necessary for carbonization; generally, qualified coke can be obtained after 48 to 72 hours. At the end of the 18th century, coal was used to produce household gas. In 1792, the Scot W. Murdoch used an iron retort to dry-distill bituminous coal, and the resulting gas was used for household lighting. In 1812, this type of carbonized gas was first used for street lighting in London, and later it was adopted by some major cities around the world as well. In 1816, a coal carbonization plant was established in Baltimore, United States, to produce gas. From then on, the industry of dry-distilling coal in iron retorts gradually developed. In 1840, France used coke to produce producer gas for iron smelting. In 1875, the United States began producing heated water gas for use as city gas. Between 1850 and 1860, France and other countries in Europe successively established coking plants. By this time, coke ovens had begun to use rectangular, two-sidedly heated retorts made of refractory materials. Each end of the chamber was equipped with a closed iron door that could be opened during coke pushing; this type of furnace was the precursor to modern coke ovens. Although coke is the main product of coking, the recovery of coking chemicals has also attracted attention. In the 1870s, Germany successfully developed coke ovens equipped with chemical recovery systems, which enabled the extraction of large quantities of aromatics from coal tar for use as raw materials in industries such as pharmaceuticals, pesticides, and dyes. During World War I, the steel industry developed at a rapid pace; at the same time, ammonia, benzene, and toluene, which are used as raw materials for explosives, were in high demand. This led to further development of the coking industry, as well as the emergence of an industry focused on the recovery and utilization of chemicals produced as by-products of coking. In 1925, China built its first coking plant in Shijiazhuang to meet the coke needs of the Hanye Ping ironworks. Between 1920 and 1930, research on low-temperature carbonization of coal received attention and developed rapidly; the semi-coke produced could be used as a smokeless fuel for domestic use, while the tar obtained from low-temperature carbonization was further processed into liquid fuels. In 1934, a gas plant equipped with vertical retort furnaces and water-gas heaters was built in Shanghai, China, to produce city gas. Period of Comprehensive Development: On the eve of and during World War II, coal chemistry experienced comprehensive and rapid development. In order to launch and sustain war, Nazi Germany carried out extensive research on the production of liquid fuels from coal, accelerating the industrial production of such fuels. The Fischer-Tropsch process, invented in 1923 for synthesizing liquid fuels from carbon monoxide and hydrogen, began industrial production in 1933, with production reaching 590 kt by 1938. In 1931, F. Burgess was awarded the Nobel Prize in Chemistry for his successful direct liquefaction of coal to produce liquid fuel. This method of producing liquid fuel through high-pressure hydrogenation of coal reached an annual production capacity of 1.10 Mt by 1939. During this period, Germany also established large-scale low-temperature retorting plants; using briquetted coal made primarily from lignite with a small amount of bituminous coal as raw material, it developed the Krupp-Ruhry external-heating retorting furnace and the Ruhry-Spielges internal-heating retorting furnace. The resulting semi-coke is used for gas production, while the tar obtained through catalytic synthesis is used to produce liquid fuels; the tar from low-temperature carbonization, after simple treatment, serves as fuel for naval ships, or it can be converted into gasoline and diesel through high-pressure hydrogenation. By 1944, the annual production capacity of low-temperature carbonization tar had reached 945 kt. Towards the end of World War II, Germany produced 4 Mt of liquid fuel per year from coal and coal tar using hydrogenation liquefaction; the total amount of liquid fuel produced from coal reached 4.8 Mt per year. Meanwhile, the industry also extracts various aromatic and heterocyclic organic products from coal tar, which are used as raw materials for dyes and other substances. In addition, small-scale industries that produce sulfonated coal, humic acid, and lignite wax through direct chemical processing of coal have developed, as well as the chemical industry that uses coal as a raw material to produce calcium carbide, from which acetylene is then generated for further use. During the period of recession, after World War II, thanks to the large-scale extraction of cheap oil and natural gas, industrial production of liquid fuels from coal was temporarily halted, with the exception of the coking industry which continued to develop alongside the steel industry. In many industrial applications, natural gas replaced domestic gas. The rapid development of the petrochemical industry, which uses oil and gas as raw materials, has led to a **decline in the significance of the acetylene chemistry industry based on coal**. It is worth noting that due to its unique geographical and political environment as well as its resource conditions, South Africa has seen continuous development in the industry for synthesizing liquid fuels from coal as a raw material. In 1955, the industrial plant for the SASOL-Ⅰ Fischer-Tropsch synthesis process was built. In 1977, a large-scale fluidized-bed reactor was developed, followed by the creation of SASOL-Ⅱ and SASOL-Ⅲ. In 1982, two artificial oil production plants with an annual capacity of 1.6 Mt each were built. Technology development period: The Middle East War in 1973 and the subsequent sharp rise in oil prices led to a renewed interest in methods for producing liquid fuels and chemicals from coal. Countries in Europe and the United States have carried out further research and development on this, making progress. Methods such as the hydrogen-coal method, the hydrogen-supplied solvent method (EDS), and the solvent-refined coal method (SRC) have been developed in the field of direct coal liquefaction ； The SASOL process was developed within the indirect coal liquefaction method; coal is gasified to produce syngas, which is then used to synthesize engine fuel ； Synthesized methanol can also be further converted into high-quality gasoline, or used directly as fuel methanol. Due to the high consumption of oil and the abundant availability of coal, coal chemical industry will see further development.