In this article a convenient method for the synthesis of novel piperazine based bis(4-hydroxy-2Hchromen- 2-one) derivatives using pyrazine-1,4-diium tricyanomethanide {[1,4-DHPyrazine][C(CN)3]2} as a new nanostructured molten salt (NMS) catalyst has been described. These compounds were synthesized via Mannich type reaction between several aromatic aldehyde, piperazine and 4-hydroxycoumarin under solvent-free condition at room temperature. The NMS catalyst was fully characterized via Fourier transform infrared (FT-IR), nuclear magnetic resonance (1H NMR and 13C NMR), mass spectrometry, thermal gravimetric, derivative thermal gravimetric, differential thermal analysis, X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy analysis. The new compounds synthesized by using this NMS catalyst were also characterized by FT-IR, 1H NMR and 13C NMR, high-resolution mass spectrometry techniques.
