Fifteen compounds belonging to chemical series 2-amino-6-(2,3-dioxo-1,2,3,4tetrahydroquinoxalin-1-yl)-4-(substituted)phenylpyridine-3-carbonitrile (3a-o) were synthesized by a multistep scheme and evaluated for their in vitro antibacterial and antifungal activities against bacterial strains E. coli, S. aureus, P. aeruginosa, K. pneumonia and antifungal activity against fungal strains A. niger, C. albicans and A. flavus by cup-plate diffusion method. Structures of all the newly synthesized compounds were confirmed by FT-IR, 1 H NMR and ESI-MS spectral data interpretation and elemental analysis. Compounds 3e, 3k, 3l, 3m and 3n having functional groups viz. 4-CF 3 , 4-NO 2 , 2-F, 2-NO 2 , 4-F respectively on phenyl ring attached to position-4 of pyridine ring attached to N-1 of (1H,4H)quinoxaline-2,3-dione exhibited better antibacterial and antifungal activities against all the bacterial and fungal strains under investigation.