New complexes of N-isonicotinamido-4-chlorobenzalaldimine (INHCBA) with Cu(II), Co(II) and Cd(II), having formula of the type [M(INHCBA)(ac) 2 ]·xH 2 O (M = Cu 2+ , x = 1, M = Co 2+ , x = 2, M = Cd 2+ , x = 0, ac = CH 3 COO -), and with Cu(II), Mn(II) and Zn(II), having formula of the type [M(INHCBA) 2 (H 2 O) 2 ]SO 4 ·xH 2 O (M = Cu 2+ , Mn 2+ , x = 2 and Zn 2+ x = = 2.5) were synthesized and characterized by analytical and physico-chemical techniques, i.e., elemental analyses, IR, UV-Vis-NIR and EPR spectroscopy as well as thermal analysis and the determination of the molar conductivity and magnetic moments. The thermal behaviour of complexes was studied by thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The ligand behaves as bidentate NO, being coordinated through the azomethine nitrogen and carbonylic oxygen. The heats of decomposition, ΔH, associated with the exothermal effects, were also determined.