synthesized as newpotential antimicrobial agents by facile multi‐step procedure from o‐aminobenzoic acids and 2‐acetylthiazole. A series of biological evaluation showed that compound 7d was the most effective quinazolonethiazole with superior activity to reference drugs chloramphenicol and norfloxacin. This active molecule displayed unobvious bacterial resistance against P. aeruginosa, the low toxicity