The new complexes CuX2(LH2), CuX2(SH3) (X = Cl, Br), CuX(LH2), CuX(SH3) (X = Cl, Br, I), CuX(H4MTO)2(X = Cl, Br), Cul(H4MTO) and CuX(H3MMTO)2(X = Cl, Br, I), where LH2= N.N′-dimethyl-monothiooxamide, SH3= N(s)-methylmonothiooxamide, H4MTO = monothiooxamide and H3MMTO = N(o)-methylmonothiooxamide, have been prepared. The complexes were characterized by elemental analyses, conductivity measurements, magnetic moments and spectroscopic (UV/VIS, FT-IR, Laser-Raman) studies. The vibrational analysis of the complexes has been given using NH/ND, CH3/CD3and63cu/65cu isotopic substitutions. The neutral monothiooxamides behave as monodentate ligands in the Cu(I) complexes coordinating through their thioamide sulfur atom. The ligands LH2 and SH3act as bidentate chelating agents in the Cu(II) complexes with ligated atoms being the thioamide sulfur and the amide oxygen.