The interaction of M-II ions (M-II = Mn-II, Co-II, Ni-II, Cu-II, Zn-II, Cd-II, Pb-II) with N-(2-nitrophenylsulfonyl)glycine (NO(2)psglyH(2)) leads to the formation at acidic pH of the complex carboxylate-type M(NO(2)psgly-O)(2).xH(2)O species. At higher pH the deprotonation reaction of the sulfonamide nitrogen takes place, leading to the formation of the M(NO(2)psgly-N,O).xH(2)O species where the ligand acts as a chelating agent toward the metal ion through the carboxylic oxygen and the deprotonated sulfonamide nitrogen. In ternary systems the addition of 2,2'-bipyridine (bpy) allows the deprotonation of the sulfonamide nitrogen also in presence of metal ions such as Zn-II, Co-II and Ni-II, which were inactive in the binary system, and the solid compounds isolated are in the M/bpy/L molar ratio 1 : 1 : 1 (M-II = Cu-II, Zn-II) or 1 : 2 : 1 (M-II = Co-II, Ni-II, Cd-II). Here we describe the crystal and molecular structures of NO(2)psglyH(2) (1), [Pb(NO(2)psgly-N,O)](n) (2), [Cd(bpy)(2)(NO(2)psgly-N,O)].H2O (3) and [Cu(bpy)(NO(2)psgly-N,O)(H2O)] (4).