A series of naphtho[2,3-d]imidazoles (2a-l) were synthesized in good yields by the reaction of 2,3-diaminonaphthalene with aromatic aldehydes in the presence of catalytic amounts of copper nitrate, Cu(NO3)2.6H2O. Some features of this practical protocol are: use of catalyst, short reaction times and easy workup. The antibacterial activity of these naphtho[2,3-d]imidazoles was tested against Staphylococcus aureus (mm) and Escherichia coli (mm) bacterial strains.