Abstract An efficient synthesis of novel 2-aryl-3-(phenylamino)-2, 3-dihydroquinazolin-4 (1H)- one derivatives using KAl (SO 4) 2. 12H 2 O (Alum) as a catalyst from an aldehyde and 2- amino-N-phenylbenzohydrazine in ethanol is described. All synthesized derivatives were screened for anti-bacterial activity. Some compounds exhibited promising anti-bacterial activity with reference to standard antibiotics.