This study explores the synthesis, characterization, and biological activity evaluation of thiopyrimidone derivatives derived from chalcone precursors. Heterocyclic compounds play a crucial role in medicinal chemistry, given their presence in many pharmaceutical agents. Our research focuses on synthesizing various chalcones through Claisen-Schmidt condensation and their subsequent transformation into thiopyrimidone derivatives via condensation with thiourea. Characterization of these compounds was performed using Proton NMR (1H NMR), Carbon-13 NMR (13C NMR), IR spectroscopy, and mass spectrometry, ensuring precise identification and structural integrity. The synthesized compounds were then assessed for their antibacterial activity against four bacterial strains: E. coli, B. subtilis, B. amyloliquefaciens, and B. megaterium, using nutrient agar and broth methods. Comprehensive 2D and 3D plots illustrated the dose-dependent responses of % cell viability across various concentrations, highlighting the IC50 values of each compound. Among the tested derivatives, B4 emerged as the most potent compound with consistent IC50 values around 20 μg/mL, significantly outperforming kanamycin, which exhibited IC50 values near 80 μg/mL. The variations in efficacy across different strains underscore the importance of strain-specific evaluations in antimicrobial research. Our findings suggest that B4 holds significant promise as a therapeutic agent, providing a foundation for future optimization and mechanistic studies. This research contributes to the advancement of heterocyclic chemistry and the development of novel antimicrobial agents, demonstrating the potential of thiopyrimidone derivatives in addressing antimicrobial resistance and expanding the arsenal of effective therapeutic compounds.