A facile, green approach for the synthesis of some new dibenz[1,4]-diazepine-1-one by a three component reaction of Diamine, 1,3 diketone and aromatic aldehyde using oxalic acid as catalyst in water is described. The products are formed in good yields (92–94%). Newly synthesized dibenz [1,4]-diazepine-1-one analogues were evaluated for the anxiolytic activity by the elevated plus maze method. From the activity data it is observed that compounds, 4g, 4h and 4k show promising anxiolytic activity.