Two copper(II) complexes type [Cu(en)X2](ClO4)2, where en = ethylenediamine and X = pyridine, 1 or imidazol, 2 have been synthesized and prepared on the bases of elemental analysis, spectroscopic and molar conductance measurements. The X-ray crystal analysis of these complexes demonstrated that the copper(II) ions are in square planar environments through coordination by two nitrogen atoms of the ethylenediamine and two nitrogen atoms of two pyridine or imidazol molecules and the ClO4- ions are bound weakly above and below of themolecular plane. The complexes show three ions behavior in all solvents. The complexes are soluble in various solvents and are solvatochromic. The solvatochromismof the complexes were investigated by UV-Vis spectroscopy with different solvent parameters such as DN, AN, and using multiple linear regression (MLR) method. The results suggested that the DN parameter of the solvent has the most contribution to the shift of the d-d absorption band of the complex 1 but in complex 2 the DN and have almost similar importance in the observed variation in the shift of the max values with solvent nature.
