Substituted-3-formylchromones (4a-e) on reaction with 1,3-bis-dimethylaminomethylene-thiourea (5) in refluxing toluene solution give novel substituted 5-(o-hydroxyaroyl)pyrimidines (6a-e) in high yields. A mechanistic rationalization of the formation of products (6a-e) is proffered. Antimicrobial activities of all the synthesized compounds (6a-e) were evaluated against various fungal and bacterial strains. Compound 6d display significant antifungal activity (MIC 15) against Geotrichum candidum in comparison fluconazole used as positive control. Some of the compounds also display good antibacterial activity. Cytotoxic profile of compound 6d against HeLa cells indicates that at concentration (20 μM) no significant cell death (~2%) was observed.