Abstract Two new copper(II) complexes of composition [trans-Cu(en) 2(H 2O) 2](L 1) 2, 1 and [trans-Cu(en) 2(H 2O) 2](L 2) 2, 2 (L 1 = p-toluenesulphonate, L 2 = 5-bromo-2-methoxybenzenesulphonate) were obtained by the addition of ethylenediamine to hydrated Cu(II) sulphonates, Cu(L 1/L 2) 2· nH 2O in methanol–water solution. The newly synthesized complex salts have been characterized by elemental analyses, TGA, spectroscopic techniques (electronic and FT-IR), magnetic moment determination and conductance measurements. The complex salt 1 crystallizes in the monoclinic system with space group P2 1/ c and complex salt 2 crystallizes in the triclinic system with space group P 1 ¯ . X-ray structure determination revealed ionic structures consisting of one complex cation [Cu(en) 2(H 2O) 2] 2+ and two respective sulphonate anions in 1 and 2. A three dimensional hydrogen bonding network formed by N–H…O, C–H…O and O–H…O through second sphere interactions besides electrostatic forces of attraction stabilize crystal lattice in both complex salts.