It is a colorless solid, but samples take on a reddish color in air because of oxidation.

It was formerly used to make azo dyes, but it is a known carcinogen and has largely been replaced by less toxic compounds.

When reduced by sodium in boiling amyl alcohol solution, it forms tetrahydro-3-naphthylamine, which exhibits the properties of the aliphatic amines in that it is strongly alkaline in reaction, has an ammoniacal odor and cannot be diazotized.

Of them, the δ-acid and Bronner's acid are of more value technically, since they combine with ortho-tetrazoditolyl to produce fine red dye-stuffs.

[3] 2-Naphthylamine is found in cigarette smoke and suspected to contribute to the development of bladder cancer.