Xylenes are a group of three isomers of dimethylbenzene, which are organic compounds made up of a benzene ring with two methyl groups attached. The three isomers are ortho-xylene, meta-xylene, and para-xylene, each differing in the arrangement of the methyl groups. Xylenes are colorless liquids with a sweet odor and are commonly used as solvents in various industrial applications, including paint thinners and varnishes. In addition to their use as solvents, xylenes are important in the production of petrochemicals and can be converted into other chemicals, such as phthalic anhydride and styrene. They are also found in small amounts in gasoline and are released into the environment through vehicle emissions and industrial processes.