An efficient, one-pot synthetic protocol toward spirooxindole derivatives containing 1,4-dihydropyridine-fused 1,3-diazaheterocycle fragments, a class of biologically active compounds starting from 1,1-bis(methylthio)-2-nitroethylene, 1,n-diamine, isatin, or its derivatives, and malononitrile is described. The reaction proceeds in ethanol in the presence of 10 mol% of piperidine as a basic catalyst