Naphthyridine is a class of aromatic heterocyclic compounds whose chemical formula is C8H6N2. They consist of naphthalene bicyclic rings in which two carbon atoms are replaced by nitrogen atoms. There are ten isomers of naphthyridine, because naphthyridine has two benzene rings, has strong π-π conjugation, and has better luminescence properties. Common naphthyridines are 1,8-naphthyridines. There are many kinds of 1,8-naphthyridine derivatives, and they are widely used.
Naphthalene is a hydrocarbon produced by the distillation of coal tar and is an aromatic white crystalline substance. Naphthalene is the most abundant component in coal tar. It is used as an insect repellant and insect fumigant. The compound is used in the manufacture of celluloid, dyes, hydrogenated naphthalenes, oil fumes, smokeless powders and synthetic resins.