Abstract Seven 5-acetyl-4-aryl-6-methyl-3,4-dihydropyrimidin-2(1H)-thiones 10-16 are prepared by a one-pot cyclocondensation reaction of acetylacetone (1), thiourea (2) and aldehyde (3-9) in ethanol using calcium fluoride as the catalyst is described. All the compounds are screened for their antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi and antifungal activity against Candida albicans, Aspergillus flavus, Rhizopus and Mucor. Ciprofloxacin is used for the standard for antibacterial and Amphotericin B is used for the standard for antifungal studies. Compounds 12-15 exhibited excellent in vitro antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Whereas the same set of compounds exerted potent in vitro antifungal activity against Candida albicans and Aspergillus flavus
