The complexes of the type ML₂ (SCN)₂ have been synthesised from M (SCN)₂ [M=CO(II), Ni(II)] and N-substituted thioureas (L) such as chlorophenyl (Cl-Ptu), tolyl (totu), methoxy phenyl (meo-ptu), nitrophenyl (NO₂-Ptu) and bromophenyl (Br-Ptu) thioureas. All the complexes are non-electrolytes in acetone.ir spectral studies reveal that thiourea and thiocyanate are bonded to the central metal through S and N respectively. Magnetic susceptibility studies at room temperature (25°C) and electronic spectral data confer octahedral symmetry to nickel (II) and tetrahedral symmetry to cobalt (II) complexes.

Several mixed ligand complexes of nickel(II) and cobalt(II) acetylacetonates with N-substituted thioureas such as ortho, meta and para chlorophenyl, parabromophenyl and orthotolyl thioureas and N,N′-substituted thioureas such as N-benzoyl N′-ethyl thiourea, N-benzoyl N′-phenyl thiourea, N-benzoyl N′-o-chlorophenyl thiourea, N-benzoyl N′-o-tolyl thiourea, N-benzoyl N′-o-methoxyphenyl thiourea, N-benzoyl N′-cyclohexyl thiourea, N-benzoyl N′-2,5 dimethoxyphenyl thiourea, N-benzoyl N′-2,5 diethoxyphenyl thiourea, N-benzoyl N′-β-hydroxyethyl thiourea, N-benzoyl N′-furfuryl thiourea, N-benzoyl N′-orthohydroxyphenyl thiourea and N-phenyl N′-orthomethoxyphenyl thiourea, have been synthesized and characterized on the basis of elemental analysis, conductivity, molecular weight determination and magnetic moments. The nature of the bonding and the structure of the complexes have been proposed from the infrared and electronic spectral studies.