The current study is aimed at the synthesis of these quinazolinone derivatives 7-Chloro-2-Methyl-4H-benzo[d]-[1,3]-Oxazin-4-one and 3-Amino-7-Chloro-2—Methyl-3H-Quinazolin-4-One and evaluate them for their antibacterial activity.The condensation of 2-amino-methyl-4-methoxybenzoate with acetic anhydride yielded the cyclic compound 2-methyl-4, 5-disubstituted-1, 3-benzo-oxazine-4-one which further produce a novel 2,3-disubstituted quinazolin-4 ones via the reaction with hydrazine hydrate The quinazolinone derivatives 7-chloro-2-methyl-4H-benzo[d][1,3]-oxazin-4-one and 3-amino-7-chloro-2-methyl-quinazolin-4(3H)- One were evaluated pharmacologically for their in vivo analgesic activities by acetic acid induced writhing in mice. The compounds synthesized were unequivocally confirmed by means of Infrared, Nuclear Magnetic Resonance (1H and 13C), Gas Chromatography Mass Spectrophotometer and Elemental analysis.The synthesized compounds were screened against various strains of microorganism; Klebsiella pneumonia, Staphylococcus aureus, Bacillus species, Escherichia coli, Klebsiella pneumonia, , and Candida albicans. Compounds 1and 2 showed significant activity against Klebsiella pneumonia, Staphylococcus aureus and Pseudomonas aeruginosa with MIC ranging from 6 – 9 mg/mL. The test investigated compounds exhibited significant antibacterial activity against the bacteria when compared with the control test sample. The IR spectra of compound 1 were characterized by absence of υ NH2and presence of υ C-O stretch in 1157 cm-1 region of the compound. Compound 2 was characterized by absence of υ C-O and presence of υNH2 in 3285 cm-1and 3184 cm-1 region of the compound. The compounds synthesized exhibited promising antibacterial activities against Klebsiella pneumonia, Staphylococcus aureus and Pseudomonas aeruginosa, stock cultures. The compounds have high activity against the microorganisms. Compound 2 has a higher activity against Klebsiella pneumonia, Styphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus compared to Compound 1.