New complexes and adducts of xanthate of the general formula [M(cyclopentyl xant.)2] and [M(cyclopentyl xant.)2.nL] Where M= Mn(ΙΙ) Fe(ΙΙ), Co(ΙΙ), Ni(ΙΙ), Cu(ΙΙ) and Zn(ΙΙ), and (cyclopentyl xant.)2=[Cyclopentyl xanthate ligand], n=2 L= Pyridine, 3-acetyl pyridine & Quinoline n=1, L= ethylenediamine, (1,10)-phenanthroline, the prepared complexes has been evaluated based on their magnetic, electrical, and physical characteristics. And spectral methods 1H-NMR of (cyclopentyl xant.) ligand, Based on the effective magnetic moment and electronic spectra, the structures of the kind [M(cyclopentyl xant.)2] indicate a tetrahedral geometry whereas structures of the kind [M(cyclopentyl xant.)2.nL] has an octahedral geometry. The density functional theory (DFT) calculations of ligands and their complexes were performed by the DFT/B3LYP/6-311++G(d,p) method to obtain the optimized molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and electronic properties , thermodynamic parameters are done for four coordinates