Some new heterobicyclic nitrogen systems 5-18 and/or thioethers 20, 22 bearing the 1,2,4-triazine moiety have been synthesized via condensation of 3-formylamino-1,2,4-triazine 3 with nitrogen compounds followed by heterocyclization with oxygen reagents. Thioether analogs 20, 22 have been obtained from fusion of compound 19 with 4-chlorothiophenol. The structure of the products have been established by elemental analysis and spectral data. The anti-HIV and anticancer activities of some products have also been investigated where compounds 20a, c and 22b exhibited a moderate activity. The biocidal-structures activity correlation was also studied.