Imidazole-based ionic liquid-stabilized on silica coated Fe3O4 magnetic nano particles [nano-Fe3O4@SiO2@(CH2)(3)-Imidazole-SO3H]Cl as a novel heterogeneous acidic catalyst was designed, synthesized and fully characterized by FT-IR, thermo gravimetric analysis (TGA), differential thermal analysis (DTA), energy-dispersive x-ray spectroscopy (EDX), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Brunauer-Emmett-Teller (BET) and inductively coupled plasma (ICP) analysis. The nano-structured organo solid catalyst as a novel, mild and full-fledged catalyst was used for the cascade synthesis of 1,8-dioxo-octahydroxanthene derivatives by the condensation reaction between dimedone and various aldehydes at 80 degrees C under solvent-free conditions. Similarly, dihydropyrano[2,3-c]pyrazole derivatives were synthesized by the one-pot three-component condensation reaction of aldehydes, malononitrile and 3-methyl-1-phenyl-2-pyrazoline-5-one under solvent-free conditions at room temperature. To the knowledge of our science, this is the main investigation on the synthesis of [nano-Fe3O4@SiO2@(CH2)(3)-Imidazole-SO3H]Cl as a worthy heterogeneous nano magnetic solid acid for acid catalyzed organic reactions. (C) 2016 Elsevier B.V. All rights reserved.