Enaminonitrile 2 was used as key intermediate for the synthesis of polyfunctionally substituted heterocycles (e.g. pyrazoles, isoxazole, pyrimidines, thiazolo[3,2-a]pyrimidine, tetrazolo[1,5-a]pyrimidine, pyrido[1,2-a]pyrimidine, 1,5-benzodiazepine, and pyrazolo[1,5-a]pyrimidine) incorporating benzothiazole moiety via its reactions with some N-nucleophiles. The newly synthesized compounds were characterized by IR, (1)H NMR and mass spectral studies. Representative compounds of the synthesized products were tested and evaluated as antimicrobial agents.