Treatment of 4-((3,5-diamino-1H-pyrazol-4-yl)diazenyl)-N-(thiazol-2-yl)benzenesulfonamide (1) with malononitrile, 2-(ethoxymethylene)malononitrile, ethyl 2-cyano-3-ethoxyacrylate and diethyl 2-(ethoxymethylene)malonate afforded pyrazolo[1,5-a]pyrimidine derivatives 2-5. Also, compound 1 was react with ethyl 3,5-diphenylcyclohexanone-2-acetate (6) afford pyrazolo[5,1-b]quinazoline derivative 7. Moreover, the reaction of aminopyrazole 1 with enaminones 8, 10 in glacial acetic acid gave pyrazolo[1,5-a]pyrimidine derivative 9 and pyrazolo[1,5-a]quinazoline derivative 11. Furthermore, the reaction of aminopyrazole 1 with enaminonitriles 12, 14 gave pyrazolo[1,5-a]pyrimidine derivatives 13 and 15, respectively. The newly prepared compounds were screened for their biological evaluation as antimicrobial activities.