Diphenylamine is mainly used as antioxidant of synthetic rubber, intermediate of fuel and medicine, antioxidant of lubricating oil and stabilizer of gunpowder.

Determination of nitrate, chlorate and other oxidizing substances. Catalytic determination of iridium. Photometric determination of nitrate. Redox indicator. Haploid breeding medium. Make dyes. It is a stabilizer for nitrocellulose, explosives and collodion.