Here, we present the synthesis of multifunctionalised 2-substituted benzimidazoles by condensation of aldehydes or aromatic carboxylic acids with O-phenylenediamine utilizing Vitamin B 12 as effective solid catalysts. These solid catalysts gave better yields (90% - 95%) in short reaction time (2-5 min) using microwave irradiation methodology. Where as in conventional methods gave better yields (85%-95%) in 50 100 min. Both methodologies were simple, robust, and convenient and gives excellent to good yields (90-95%) and shorter reaction times. These cheap, widely available catalysts are more active than a large number of costly reported heterogeneous catalysts. This methodology was found to be efficient for the synthesis of 2 Substituted benzimidazole derivatives with interesting characteristics such as simple workup procedure, high atom economy and excellent to good quality of product.