In the present study 1, 5-benzodiazepines were synthesized from a range of alpha, beta-unsaturated ketones and o-phenylendiamine using oxalic acid 10 mol% as a catalyst under solvent free conditions. The yields of the present method are better than the reported method which explains effectiveness of oxalic acid catalyst. The cost effective, resourceful, undemanding and environment friendly are the advantageous aspects of this method.