Nicotinamido-4-bis(2-chloroethyl)aminobenzaldimine (NBAB) was synthesized and characterized by elemental analysis, IR and 1H NMR spectra. The complex of Cu(NBAB)2(NO3)2 was prepared in ethanol and characterized by elemental analysis, conductivity, cyclic voltammetry, IR, UV-Vis, fluorescence, CD and EPR spectra. The characteristic data suggest that the complex has an elongated octahedral structure, and NBAB behaves as bidentate in the keto form. The antitumor activities of NBAB and the complex against L1210 murine leukemia and K562 were investigated with both the MTT method and the colony formation test. The results in vitro indicate that antitumor activities of NBAB are superior to 2,2'-chlorodiethylamine hydrochloride (nitrogen mustard) for L1210, and inferior to nitrogen mustard for K562, but the antitumor activities of the complex for both cell lines are superior to nitrogen mustard.