A diamine is an organic compound with two amino groups. Diamines are used as monomers to prepare polyamides, polyimides, and polyureas. In terms of quantities produced, 1,6-diaminohexane, a precursor to Nylon 6-6, is most important, followed by ethylenediamine.[1] Vicinal diamines (1,2-diamines) are a structural motif in many biological compounds and are used as ligands in coordination chemistry.[2]