In the present work the desired quinazolinone derivatives (DK-1, DK-2, DK-3, DK-4, DK-5, DK-6 & DK-7) were synthesized by treating 2-Chloro-N-(4-oxo-2-phenylquinazolin-3(4H)-yl) acetamide (I-1) with the different substituted phenols in presence of anhydrous potassium carbonate & catalytic amount of potassium iodide in dry acetone. The structures of the newly synthesized compounds have been established on the basis of their m.p., TLC, IR and 1HNMR data. All the newly synthesized quinazolinone derivatives were evaluated for their antibacterial activity by cup plate method by measuring inhibition zone. Ampicillin was used as standard drug. The compound DK-2 showed more potent antibacterial activity than the standard drug ampicillin.