Benzopyran is an
polycyclic organic compound that results from the fusion of a
benzene ring to a
heterocyclic pyran ring. According to
IUPAC nomenclature it is called
chromene. There are two isomers of benzopyran that vary by the orientation of the fusion of the two rings compared to the oxygen, resulting in 1-benzopyran (
chromene) and 2-benzopyran (
isochromene)—the number denotes where the oxygen atom is located by standard
naphthalene-like nomenclature.