4,4'-Dichloro-N,N'-(o-phenyl-ene)dibenzene-sulfonamide.

The title compound, C(18)H(14)Cl(2)N(2)O(4)S(2), is a diamine that is a precursor to a quinonoid bidentate redox-active ligand. The dihedral angles between the central phenyl ring and the end rings are 87.5(1) and 60.7(1)°, while the two end rings make a dihedral angle of 82.5(1)°. The crystal structure is stabilized by two weak inter-molecular N-H⋯O hydrogen bonds, as well as one intra-molecular C-H⋯O and one N-H⋯N hydrogen bond.