Mn doped zirconia is utilized as an environmental-friendly and efficient catalyst for an ultrasound mediated four-component coupling reaction, containing dimethylacetylenedicarboxy late/ethyl acetoacetate, hydrazine hydrate, malononitrile, and aromatic aldehyde. These reactions were performed under green solvent conditions, to yield pyrano[2,3-c]pyrazole-3-carboxylate/pyr ano[2,3-c]pyrazole-5-carbonitrile derivatives (5a-g and 7a-g) with good to excellent yields (88-98%). The structures of the

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... ompounds were identified and confirmed by 1 H NMR, 15 N NMR, 13 C NMR, FT-IR and HR-MS spectral data. The prepared catalyst Mn/ZrO 2 was synthesized and fully characterized by various techniques including P-XRD, BET, SEM and TEM analysis. The main benefits of this process are short reaction times, easy work-up, reusability of the catalyst and no chromatographic purifications.