A series of novel benzimidazole derivatives was synthesized and evaluated for their anti-hepatitisBvirus (HBV) activity and cytotoxicity in vitro. Strong activity against HBV replication and low cytotoxicity were generally observed in these benzimidazoles. The most promising compounds were 12a and 12b, with similar high antiviral potency (IC50 = 0.9 and 0.7 microM, respectively) and remarkable selectivity