Two new copper(II) and nickel(II) complexes [M(NC-C6H4COO)2(C6H6N2O)(2)(H20)(2)] (where M:Cu and Ni) have been synthesized and characterized by elemental analysis, FT-IR and UV Vis spectroscopy, spectroscopic ellipsometer (SE), X-ray crystallography, thermal analysis and molar conductivity. X-ray measurements showed that both of the complexes crystallized in triclinic system with the space group P-1. The isostructure complexes have distorted octahedral geometry around the metal atom center. In both of the crystal structures, the metal atoms are coordinated by two nitrogen atoms from two different nicotinamide ligands, two carboxyl oxygen atoms from two different 4-cyanobenzoate anions and two oxygen atoms from two different water molecules. From the linear absorption spectra and spectroscopic ellipsometer measurements, it was observed that these complexes showed different optical behaviors. (C) 2017 Elsevier B.V. All rights reserved.