A series of new pyrazolopyrimidines 4a,b, 5 , 8, and 11 were prepared by reaction of 3,5-diaminopyrazole 2 with active methylene reagents, arylidenemalononitrile 6 or ethyl 2-cyano-3,3-bis(methylthio)acrylate 9 . Also new pyrazolo[5,1-c]-[1,2,4]triazine 13 was prepared by reaction of 1-nitroso-2-naphthol 12 with 2. The antibacterial and antifungal activities were screened for the new compounds and compound 11 exhibited the highest potency against all tested organisms.