Reaction of cyanoacetohydrazones 3a,b with a variety of arylidenemalononitriles 5a - c under the effect of piperidine basic catalysis afforded exclusively the corresponding 6-amino-1,2-dihydro-1,4- disubstituted-2-oxo-3,5-pyridinedicarbonitriles 6a - f in high regioselectivity. A chemical confirmation for the proposed structure was achieved through the reaction of ylidenes 8 with malononitrile under basic conditions, which yielded the corresponding 6 accompanied with 3. Refluxing 3b in acetic anhydride gave 2-acetyl-3-cyanomethyl-4,5-dihydro-2H-benz[g]indazole (10) as the only isolable product. Single crystal X-ray diffraction of 6e and 10 add conclusive support for the established structures.