KEYWORDSNew N-substituted-2-methyl quinazolin-4(3H)-ones derivatives comprising 1,3,4-thiadiazole, Schiff bases and 2-azetidinone moieties are reported. The structures of the newly prepared compounds were confirmed by FT-IR and 1 H NMR spectra. The compounds were also evaluated for their antimicrobial, antioxidant and study of inhibition on some enzymes activities. The results suggest that the compounds possess broad spectrum of in-vitro antimicrobial activity. Antioxidant results obtained into the present study indicate that compound 5 show moderate better scavenging activity. Compound 5 demonstrated inhibitory effects on GOT, GPT, GGT and ALP activities, and these effects increase with increasing the concentration of the compound.Schiff bases Azetidinone Quinazolinone Enzymes activities Antioxidant activity Antimicrobial activity