Even though many workers have studied solute–solvent interactions of paramagnetic complexes in solutions through the spin-Hamiltonian constants, the attempts made to find a single parameter to study the above are less. From a study on a number of Cu(II) complexes, the authors found that the amount of 4s-character present in the ground state of Cu(II) indicated the nature of the symmetry of the chromophore around Cu(II). In the present investigation six Cu(II) complexes viz., ( i)[Cu(trien)](ClO 4) 2,( ii)[Cu(trien)NCS] ClO 4, ( iii) [Cu(trien)Br] Br, ( iv) [Cu(trien)NCS] BPh 4,( v) [Cu(Me 6trien)NCS] ClO 4, ( vi)[Cu(Me 6trien)NCS] SCN (trien = triethylenetetramine;Me 6trien = hexamethyltrien) in DMF(N,N′-dimethylformamide)solutions are chosen to find the validity of the above procedure. From the calculations, it is found that the ground-state of Cu(II) in the ( iv) complex is free from 4s contribution indicating planar structure. Whereas in the case of the ( iii) complex, the ground-state is found to possess 0.95% of 4s character indicating strong axial bond. This 4s character in other cases is found to be less than in the above complex. From these studies it is found that 1% of 4s in the ground-state has reduced isotropic contact term (K) by about 30 MHz. Using this value, the values of K in other complexes are computed and these are found to surprisingly coincide with the values obtained experimentally within 1% error.