The first synthesis of benzonitrile tetracyanonickelate complexes, represented by the general formula M(benzonitrile)Ni(CN) (M = Ni, Zn, Cd, and Hg), is reported. Fourier transform infrared spectroscopy and Raman spectroscopic data in the region of 4,000-400 cm are presented, and the vibrational frequencies are assigned and explained in detail. The thermal behavior of these complexes was also investigated by thermogravimetric analysis, differential thermal analysis, and derivative thermal gravimetric analysis. The spectral and thermal analysis results of the newly synthesized complexes suggest that these complexes are new examples of Hofmann-type complexes. The spectral data obtained show that the complexes consist of |M-Ni(CN)| polymeric layers with the ligand (benzonitrile) molecules bound to metal through the N-donor atom of the cyanide group. [ABSTRACT FROM AUTHOR]