A water soluble, Bronsted acid, 5-sulfosalicylic acid as an efficient organocatalyst was used for the synthesis of physiologically active 2-substituted benzimidazole derivatives from o-phenylenediamine and aromatic aldehydes in ethanol at reflux condition. Cost-effectiveness, use of non-hazardous solvents, metal free and commercially available catalyst, single-step, environmentally friendly green method, high conversions, cleaner reaction profiles and simple experimental and workup procedures are the remarkable features of this method. A water soluble, Bronsted acid, 5-sulfosalicylic acid as an efficient organocatalyst has been used for the synthesis of physiologically active 2-substituted benzimidazole derivatives from o-phenylenediamine and aromatic aldehydes in ethanol at reflux condition. Cost-effectiveness, use of non-hazardous solvents, metal free and commercially available catalyst, single step, environmentally friendly green method, high conversions, cleaner reaction profiles and simple experimental and workup procedures are the remarkable features of this method. تفاصيل المقالة