Abstract Comparison of experimental and theoretical parameters pertaining to structural and spectral properties of two nickel(II) complexes containing triphenylphosphine and 5-methyl-N-(2-mercaptophenyl)salicylideneimine (1) or 5-chloro-N-(2-mercaptophenyl)salicylideneimine (2) are presented. The calculated structural results of these complexes show that the DFT can well reproduce the structure of title compounds. The UV, IR and NMR spectra of the title compounds are determined using both experimental and theoretical methods. The optical absorption properties of the title compounds are calculated using time-dependent density functional theory method (TD-DFT). The IR spectra are calculated from the harmonic vibrational frequencies at the ground-state geometry of the title-compounds. The NMR spectra are calculated using the gauge-independent atomic orbital (GIAO) method. The results calculated using theoretical methods coincide well with the experimental results.