The benzimidazole molecule (Benz) is known to play a fundamental role in many biological systems; it is moreover, extensively used in industrial processes as a corrosion inhibitor for metal and alloy surfaces. The synthesis and the thermal profile of some Cu (II) complexes of benzimidazole of general formula CuBenz(4)X(2) are proposed. A parallel study of these complexes with an ionization mass spectrometer is also reported.