Highly diastereoselective synthesis of some novel benzothiazole-substituted β-lactam hybrids was achieved starting from (benzo[d]thiazol-2-yl)phenol as an available precursor. This is the first time (benzo[d]thiazol-2-yl)phenoxyacetic acid has been used as ketene source in synthesizing monocyclic 2-azetidinones. These compounds were evaluated for their antimicrobial activities against a large panel of Gram-positive and Gram-negative bacterial strains and moderate activities were encountered. Antimalarial data revealed that adding methoxyphenyl or ethoxyphenyl group on the β-lactam ring makes compounds that are more potent. Moreover, hemolytic activity and mammalian cell toxicity survey of the compounds showed their potential as a medicine.