A novel poly ionic liquid (PIL), immobilized on magnetic nanoparticle was synthesized by polymerization (Grafting from) of 2-vinylpyridine in the presence of modified magnetic nanoparticles with acrylic acid and then converted to ionic liquid by formic acid. This bronsted acid catalyst was applied to the one-pot synthesis of tetrahydrobenzo[b]pyran and dihydripyrano[c]chromene in high yield under environmentally friendly conditions. The catalyst easily recovered by magnetic separation and was reused for 5 times and showed minor changes in catalytic activity so that the yield of product decreased from 98 to 91%. This is due to the polymer layers immobilized on the surface of the Fe3O4 nanoparticles with a high loading level of ionic liquid. The Fe3O4@poly(2-vinylpyridinium) ionic liquid (Fe3O4@p(2-VP)IL) catalyst was characterized via Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM).