This book consist of three chapters includes general introduction, synthesis of naphthaimidazole and antimicrobial activity. It deals with the synthesis of napthaimidazoles by the condensation reaction between 2, 3-naphthalene diamine and aromatic aldehydes catalyzed by the optimized quantity of HCl as a catalyst in ethanol as the solvent. A series of compounds was synthesized by conventional route and under microwave irradiation (MWI) technique. All the synthesized compounds have been characterized by using 1HNMR, 13CNMR, IR and Mass spectroscopy. All the synthesized compounds were tested for their biological activity. this book is very useful to research who are carrying research in this area.