The intermolecular cyclization of N-benzyl-2-cyanoacetamide with carbon disulfide followed by intramolecular cyclization gave thioxothiazinone 3. This compound was used to synthesize a series of novel fused furopyrrole, pyridine, pyrimidine and other azine and azole derivatives. The Michael-type reaction of compound 3 with maleic anhydride followed by pyrrole and furan cyclizations and aromatization yielded polycyclic compound 7. The [3+3]-cycloaddition of benzylidene malononitrile and its derivative to compound 3 gave pyridothiazines 10–12. The ring opening in compound 3 under the action of urea or thiourea followed by pyrimidine cyclization and subsequent air oxidation resulted in the synthesis of oxa- and thiadiazolopyrimidinones 15 and 16, respectively. The reaction of compound 3 with H2O2 in a basic medium provided pyrimidine derivative 17. The oxidation of compound 3 with Br2 in an acid medium led to bromo derivative 19. The synthesized novel compounds were characterized by elemental analysis and IR and 1H and 13C NMR spectroscopy and tested antibacterial and anticancer activities.