Commonly, 2-nitrochlorobenzene is treated with ammonia to generate 2-nitroaniline, whose nitro group is then reduced:[4] In the laboratory, the reduction of the nitroaniline is effected with zinc powder in ethanol, followed by purification of the diamine as the hydrochloride salt.

Darkened impure samples can be purified by treatment of its aqueous solution with sodium dithionite and activated carbon.

[5] o-Phenylenediamine condenses with ketones and aldehydes to give rise to various valuable products.

[7] With nitrous acid, o-phenylenediamine condenses to give benzotriazole, a corrosion inhibitor.

Mercaptoimidazole are commonly used as antioxidants in rubber production, obtained by condensing xanthate esters.