3,3'-Dinitrobenzidine is primarily used as an intermediate in the manufacture of azo dyes and pigments for textiles, plastics, and printing inks, providing high stability and colorfastness. It is also a key precursor, upon reduction to 3,3'-diaminobenzidine, for synthesizing high-performance polymers such as polybenzimidazoles and polyimides. These polymers offer exceptional thermal stability and mechanical strength, finding applications in aerospace, electronics, and advanced composites. Due to its toxicity, carcinogenicity, and reactivity, handling is strictly controlled in industrial settings with appropriate safety measures.