3-Methyl-1-phenyl-2-pyrazoline-4,5-dione (3) condenses readily with malononitrile in refluxing ethanol to yield 4-(dicyanomethylene)-3-methyl-1-phenyl-2-pyrazolin-5-one (4). Compound 4 readily reacts with aliphatic, aromatic, and heterocyclic amines to yield 4-substituted (aminocyanomethylene)-3-methyl-1-phenyl-2-pyrazolin-5-ones (8). o-Substituted arylamines afford also 4-substituted (arylcyanomethylene)pyrazolones, which readily cyclize to give the 4-azolylidene pyrazolones 9a-c. Secondary and tertiary amines and activated phenols condense with 4 by hydrogen cyanide elimination to yield compounds 10a-c and 10a, b, respectively