Pyridine-4-carboxylic acid (PYCA)-functionalized Fe3O4 nanoparticles as an organic–inorganic hybrid heterogeneous catalyst was fabricated and characterized by Fourier transform infrared, X-ray powder diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscope, and VSM techniques. The catalytic activity of the magnetic catalyst was probed through one-pot synthesis of tetrahydrobenzo[b]pyran derivatives from three-component reactions of aromatic aldehydes, malononitrile, and dimedone under solvent-free conditions. Simple procedure, high yields, short reaction time, and environmentally benign method are advantages of this protocol. The catalyst was readily separated using an external magnet and was reusable without significant loss of its catalytic efficiency.
