A new series of 2-substituted alkyl thioarylbenzimidazole derivatives were synthesized by condensing o-phenylenediamine with aryl and naphthyl thioglycolic acid. All these compounds were characterized by means of their melting point, HPLC, IR and 1H NMR spectroscopic data. The synthesized compounds (i to l) have been screened for in vitro antibacterial activity against a variety of bacterial strains. Gram-negative strain of bacteria used were Klebsiella and E. Coli while gram-positive bacterial strain used was S. aureus and E. fecalis The activity was determined using MIC. Ciprofloxacin was used as standard (2 µg/mL). The compounds have shown varying degree of antibacterial and antifungal activity.