A series of 2-aminomethylbenzimidazole (1) and 2-benzimidazolone (II) derivatives were synthesized. Imidazo-and Pyrazino-derivatives (IIIa-g) were obtained from the reaction of compound (1) with acetic anhydride, glycine, carbon disulfide, ioroform, dibromoethane, phenacylbromide or diethyloxalate. Condensation of compound (1), acid hydrazide (VII) or compound II with some aldehydes or some amines, the Schiff\'s bases (IVa-b), (VIIIA,b) or (Va-c) respectively were produced. In addition, compound (II) was reacted with acetic anhydride to afford the diacetyl derivatives (IX) which was condensed with hydrazine, urea or thiourea to yield a triazolo-or triazino-derivatives X and XIa,b respectively. The prepared compounds were tested against some fungi and bacteria. Some of these compounds were found to have antimicrobial activity.