Four novel mononuclear copper(II) complexes [Cu(dicl)(2)(2-pic)(2)] 1, [Cu(dicl) 2(3-pic)(2)](2), [Cu(dicl)(2)(4-pic)(2)] 3 and [Cu(dicl) 2(2-ampy)(2)] 4 have been synthesized. The crystal structures of the complexes 2 and 3 have been determined by X-ray crystallography. X-ray structure analysis has shown that copper(II) ions have distorted octahedral geometry in 2 and 3 and diclofenac coordinates to Cu(II) ion as a deprotonated ligand through carboxylato oxygens. Four complexes have been characterized by elemental analysis and IR spectroscopy. Their thermal stabilities have been determined by TG/ DTA/ DTG techniques. Four mononuclear complexes have shown catalytic activity on the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone exhibiting saturation kinetics at high substrate concentrations. (C) 2013 Elsevier B.V. All rights reserved.