This paper describes the synthesis of four series of 4(3H)-quinazolinone derivatives. The first series was prepared by cyclization of the intermediate 3-aryl-2-substituted thiocarbamoylhydrazonomethyl-4(3H)-quinazolinones 2a,b with ethyl bromoacetate to afford the corresponding thiazolidinonyl derivatives 3a,b. The second series were prepared by the cyclization of the intermediate 2a,b with phenacyl bromide or 4-substituted phenacyl bromide giving rise to thiazolinyl derivatives 4a-f. Furthermore, the thiazolidinonyl derivatives 5a,b were obtained by reaction of the intermediate 2a,b with thioglycolic acid. On the other hand, heating the intermediate 2a,b with acetic anhydride afforded the corresponding thiadiazolinyl derivatives 6a,b. Some of the synthesized compounds showed promising anti-inflammatory-antimicrobial activities.