The coordination behavior of copper(II) with tricarballylic acid (H3TCA) and imidazole (Imz) is described. Speciation in aqueous solution has been determined at 25 C and 0.15 M NaCl ionic strength by potentiometric measurements and EPR characterization of the species. Two new compounds CuTCAH 3H2O and CuTCAHImz 2H2O were obtained and characterized by elemental analysis diffuse reflectance, FTIR (Fourier transform infrared spectroscopy), EPR and thermal behavior. Their in vitro superoxide dismutase- mimetic activities have been tested.