Mono- and dinuclear copper(II) complexes with a tetradentate Schiff base, 4',5'-bis(salicylideneimino) benzo-15-crown-5, (SALH(2)) have been prepared and characterized by elemental analyses, magnetic moments, IR, UV/VIS, and ESR spectral studies. The elemental analyses, stoichiometry and the spectroscopic data of the complexes indicate that the copper(II) ions are coordinated by the dianion of the ligand. IR spectra show that the ligand acts in a tetradentate manner and coordinates throught (C=N) and (C-O) groups. The geometry of the metal chelates is discussed with the help of magnetic and spectroscopic measurements. (C) 1997 Elsevier Science Ltd.