Some new 4-phenyl-2,3-dihydro-6-(substitutedaminoethyl)-1 0-iodo[1,2,4]-triazino[2,3-c]-quina-zolin-5-ones 6-14 have been synthesized from 4-(phenyl-2,3-dihydro-6-methyl-10-iodo [1,2,4]-triazino [2,3-c]quinazolin-5-one 5 by introducing different heterocyclic nuclei. Compounds 5 and 6-14 have been screened for insecticidal, anti-fungal and antibacterial activities. Compound 4-phenyl-2, 3-dihydro-6-(beta-napthylaminoethyl)-10-iodo[1, 2, 4]-triazino[2,3-c]-quinazolin-5-one 14 has been found to be the most potent compound of the present study which shows mortality of insects at 190.6 min while standard Compounds exhibit at 280 min at a concentration of 5 g/L. Moreover, this compound also possesses anti-bacterial activity. The structures of these compounds have been elucidated by IR, H-1 NMR, mass spectroscopy and elemental analysis.