Development of new antimicrobial agents is a good solution to overcome drug-resistance problems. In this context, (E)-3-(anthracen-9-yl)-2-cyano-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acrylamide (3) was synthesized and allowed to react with hydrazines to afford 5-aminopyrazoles 4a,b. Also, an efficient threecomponent, two-step synthesis of 5-aminopyrazoles 7 was reported, via reaction of 2-cyano-N-(furan-2- ylmethyl)acetamide (2b), phenyl isothiocyanate and dimethylsulphate to produce the ketene N,S-acetal 6, which reacted with hydrazine hydrate to furnish 5-aminopyrazole 7. The latter was allowed to react with some electrophilic reagents and many 5-(benzylideneamino)pyrazole 8a,b, bispyrazole 9 and pyrazolo[1,5-a]pyrimidines 12, 17, 20, 22, 25, 26, 28 and 29 were obtained. The synthesized compounds were evaluated for their in vitro antibacterial and antifungal activities. Among the synthesized compounds, bispyrazole 9 showed equipotent to ampicillin and gentamycin against both of S. epidermidis (MIC 0.49μ/mL), B. subitilis (MIC 0.24μ/mL), P. vulgaris (MIC 0.98μg/mL) and K. pneumonia (MIC 0.49μ/mL), and displayed equipotent to amphotericin B versus A. clavatus (MIC 0.98 μ/mL). Azomethine derivatives 8a,b were equipotent to amphotericin B in inhibiting the growth of A. clavatus (MIC 0.98 μ/mL). Pyrazolo[1,5-a]pyrimidine 17 was equipotent to amphotericin B in inhibiting the growth of G. candidium (MIC 0.49 μ/mL). Structures of the new synthesized compounds were established by elemental analysis and spectral data.