In this work, an efficient synthesis for the preparation of some novel quinozolinones by 2 steps. In step I , various 2-substituted-3,1-benzoxazin-4-ones are formed by the reaction of anthranilic acid and acetic anhydride / benzoyl chloride / propionic anhydride. In step II , 2-substituted-3,1-benzoxazin-4-ones, which are formed in step I, are condensed with Etoricoxib. The resulting quinazolinone derivatives were characterized by IR, NMR, 13 CNMR and mass spectral analysis. The resulting quinazolinone derivatives PBE 1, PBE 2, PBE 3, PBE 4, PBE 5 were carried out for Anti inflammatory activity and Anti microbial activity. Anti inflammatory activity was determined by carragenan induced paw-odema method for 25, 50 mg/kg derivative compounds. Anti microbial activity was effective against S.aureus and E.coli by using standard drugs like Lincomycin and Cefatazidime. The compounds 6-bromo-2-phenyl-3-{[4-(5-methyl-3- phenyl-4-isoxazolyl) phenyl] sulfonyl4-(3H) quinazolinone and 6,8-dibromo-2-phenyl-3-{[4-(5-methyl-3- phenyl-4-isoxazolyl)phenyl]sulfonyl4-(3H) quinazolinone are promising ones against Staphylococcus aureus. The compounds tested 2-phenyl-3-{[4-(5-methyl-3-phenyl-4-isoxazolyl)phenyl]sulfonyl4-(3H) quinazolinone and 6-bromo-2-phenyl-3-{[4-(5-methyl-3-phenyl-4-isoxazolyl) phenyl sulfonyl 4-(3H) quinazolinone showed better anti-inflammatory activity and 6-bromo-2-methyl-3-{[4-(5-methyl-3-phenyl- 4-isoxazolyl)phenyl]sulfonyl4-(3H) quinazolinone showed lesser activity at both the doses tested. There is no significant increase in the activity with increase in the dose (50mg/kg).