A series of newly synthesized compounds of quinazolinone by various substituents was screened for its pharmacological activities. These included their action as antibacterial agents against pathogenic bacteria (Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) and as antifungal agents against Aspergillus niger and pathogenic yeast (Candida albicans). The presently investigated compounds were synthesized in higher yields, and the structure features were elucidated on the basis of IR, 1H‐NMR, and mass and elemental analysis data. These compounds were also evaluated as antioxidant agent. The results revealed that six compounds (2a, 11b, 11a, 2b, 13a, and 3c) exhibited higher antimicrobial activity against the tested pathogenic strains. In addition, it was found that compound 6a exhibited a radical scavenging activity higher than other studied compounds. [ABSTRACT FROM AUTHOR]