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A powerful, magnetic, supported, acid catalyst, NiFeO@SiO-HPWO, was prepared by chemical support of Keggin (HPWO) heteropolyacid (HPA) on silica-coated NiFeO magnetic nanoparticles. XRD, TEM, SEM, VSM, and FTIR confirmed that the keggin HPA is well dispersed on the surface of silica-coated NiFeO magnetic nanoparticles. The magnetically recoverable catalyst could be easily recycled at least six times without significant loss of catalytic activity. After full characterization, its catalytic activity was investigated in the synthesis of tetrahydrobenzo[ b]pyran and pyrano[2,3- c]pyrazole derivatives. Graphical Abstract: (1) Novel silica-coated magnetic NiFeO nanoparticles-supported HPWO was fabricated and characterized. (2) Recyclability of the catalyst. (3) Avoiding use of corrosive acid catalysts. (4) Green chemistry.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]