2-pyridyl [3H]-quinazolin-4-one derivatives fused or substituted with different oxygen or nitrogen heterocycle moieties as potential anti-tumor and anti-microbial agents were prepared, characterized and biologically screened. The synthesis process started from 5-bromo-2-[pyridin-4-ylcarbonyl]amino]benzoic acid which was converted to the crucial building block 6-Bromo-2-(pyridin-4-yl)quinazolin-4(3H)-one via two alternative routes. Compound 3 underwent halogenation reaction POCl3 and PCl5 to afford compound 6-Bromo-4-chloro-2-(pyridin-4-yl)quinazoline 4. The novel cyclized products 5a,b-10 were subsequently prepared. Some of the newly synthesized compounds 5a, 5b, 6, 7, 8, 9 and 10 were screened for their antiproliferative and antimicrobial activities against various eukaryotic and prokaryotic cells. Compound 9 showed selective antibacterial activity against Gram-positive bacteria S. aureus (IZ = 26 mm, MIC = 256 µg/ml) and may serve as a good candidate for further developmental studies.