3,3′-Diaminobenzidine, also known as 3,3',4,4'-tetraaminobiphenyl, is composed of a biphenyl backbone with amino groups attached to each of the four para carbon atoms of the benzene rings. This compound is commonly used as a ligand in coordination chemistry and catalysis, where it coordinates with metal ions to form stable complexes with various applications. It is also utilized as a starting material for synthesizing other organic compounds and polymers.