Condensation of 4- nitrosopyrazolone (1) with active methylene components namely, malo- nonitrile, acetophenone, co-cyano-acetophenone and / or 1,3- diphenylacetone gave compounds (2a-c) and (4). Treatment of (2a, 2b) with hydrazine hydrate gave the aminopyrazoles (3a, 3b). Reaction of (1) with some lıydrazines afforded derivatives (5, 6, 7a, 7b). While the condensation of (1) with hydrazine hydrate gave the bispyrazolone (8). The structures of the ring systems have been confirmed by their IR, !H-NMR and rnass spectral data.