Regioselective synthesis of 1-N-phenyl-4-(sulfonyl)benzene-1,2-diamine derivatives was carried out by the anodic oxidation of 2-aminodiphenylamine in a water/ethanol mixture in the presence of sulfinic acids as nucleophiles using both controlled-potential and constant current techniques. Our voltammetric data indicate that the anodic oxidation of 2-aminodiphenylamine produces 1-N-phenyl-o-benzoquinone diamine. This compound acts as a Michael acceptor providing 1-N-phenyl-4-(arylsulfonyl)benzene-1,2-diamines in high yields. In this new methodology, a mixture of water and ethanol was used as the solvent, a carbon rod was used as the anode and the use of toxic and/or hazardous reagents was avoided.