In organic chemistry, xylene or xylol (from Greek ξύλον (xylon) 'wood'; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula (CH3)2C6H4. They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are substituted determines which of three structural isomers results. It is a colorless, flammable, slightly greasy liquid of great industrial value.