4-Amino-3-nitrobenzoic acid is primarily used as an intermediate in the synthesis of various dyes and pigments. Its structure allows it to participate in reactions that produce colorants for textiles, inks, and coatings. Additionally, it serves as a building block in the production of pharmaceuticals, particularly in the development of compounds with potential therapeutic properties. The nitro and amino groups on the aromatic ring make it a versatile reagent in organic synthesis, enabling the creation of complex molecules for research and industrial applications.