2-cyano-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide (1) was utilized as key intermediate for the synthesis of some new coumarin 2, pyridine 3, pyrrole 4, thiazole 7, pyrido[2',3':3,4][pyrazolo[5,1-c]triazine and aminopyrazole 9. Treatment of aminopyrazole 9 with nitrous acid, 1,3-dicarbonyl compounds, enaminone, and DMF-DMA led to the formation of pyrazolo[3,4-d]triazine 10, pyrazolo[1,5-a]pyrimidines 11, 12, 14, and pyrazolo[3,4-d]pyrimidine 13, respectively. Condensation of 9 with isatin afforded Schiff base 16. The newly synthesized compounds were characterized by IR, 1H NMR and mass spectral studies. Representative compounds of the synthesized products were tested and evaluated as antimicrobial agents.