Abstarct: Ground state geometries, spectral IR and UV-Vis, analysis of frontier molecular orbitals (FMOs), Mulliken charge analysis, molecular electrostatic potential (MEP) surfaces and quantum chemical parameters for two complex [Cu(L)(H2O)2](NO3)2 and [Cu(L)(Cl)]NO3, have been studied theoretically by the Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods. is L = 1,2-bis(2-pyridylmethylthio)ethane. The optimized geometry of the complex using LANL2DZ set the Basic set for Cu and 6-311G (d, p) for atoms S, C, H, CL, O was calculated. Mulliken charge analysis showed that the negatively charged atoms carries a positive charge is as electrophilic and areas that acts as a nucleophile. Computational IR wave numbers compared with experimental results are in good agreement. Hardness, softness, bandgap, the highest occupied molecular orbital and the lowest unoccupied molecular orbital calculations using DFT was calculated. Frontier molecular orbital energy, absorption wavelength, oscillator strength, electron absorption spectra calculations for complex Octahedral solvent dimethylformamide and trigonal bipyramidal in acetonitrile solvent was determined by TD-DFT method and the transmission charge occurred mentioned in this complex