The hydrochlorides of D-(--)(I) and L-(+)-2-(α-hydroxybenzyl)benzimidazole (II) were synthesized by the method of Phillips (CA 23, 141) in which the D-(-) and L-(+) forms of mandelic acid were allowed to condense with o-phenylenediamine in acidic medium.The isomeric benzimidazoles were isolated and purified as their hydrochlorides. I.HCl [m. 210-11° (decomposition), [α]21D -82.7° (c 1, H2O)] was found to be 2.5-3 times more active than II.HCl [m. 210-11° (decomposition), [α]25D 83.2° (c 1, H2O)].