CAS Registry Number

CAS 99-56-9 — 4-Nitro-o-phenylenediamine

4-Nitro-*o*-phenylenediamine is an aromatic diamine compound primarily used as an intermediate in the synthesis of dyes, pigments, and pharmaceuticals, particularly for azo dye production and hair coloring formulations. It appears as an off-white to yellowish crystalline powder with a melting point around 180–185°C. This chemical has a CAS number of 99-56-9, molecular formula C6H7N3O2, and a molecular weight of 153.14 g/mol. Store it at ambient temperatures in a cool, dry place, away from incompatible substances. The signal word is *Warning*, indicating moderate hazard. Molekula supplies 4-Nitro-*o*-phenylenediamine from research to bulk quantities with full documentation and ISO 9001:2015 traceability.