AbstractA new series of chalcones, pyrimidines, and imidazolinone is described; chalcones (4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l, 4m, 4n, 4o) were prepared from the lead 4‐[2‐(5‐ethylpyridin‐2‐yl)ethoxy]benzaldehyde. Pyrimidines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 5o) were prepared from the reaction of chalcones and guanidine nitrate in alkali media. Imidazolinones (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6l, 6m, 6n, 6o) were synthesized from the reaction of pyrimidine and oxazolone derivatives (prepared by Erlenmeyer azlactone synthesis). The structures of the synthesized compounds were assigned on the basis of elemental analyses, IR, 1H‐NMR, and 13C‐NMR spectral data. All the products were screened against different strains of bacteria and fungi. Most of these compounds showed better inhibitory activity in comparison with the standard drugs. J. Heterocyclic Chem., (2011).