This study synthesized green sol–gel NiFe₂O₄@ZnMn₂O₄ MNCs. X-ray Photoelectron Spectroscopy, X-ray diffraction, transmission electron microscope, field emission scanning electron microscopy, energy dispersive X-ray analysis, vibrating sample magnetometer, Brunauer Emmett Teller, and elemental mapping were employed to characterize the synthesized nanocomposites. NiFe₂O₄@ZnMn₂O₄ MNCs demonstrated outstanding catalytic activity in the microwave-assisted production of tetrahydropyrimidine and polyhydroquinoline derivatives. These magnetic nanocomposites can be easily removed from reactions using an external magnet, and their efficacy remains unchanged even after undergoing four cycles.

In this study, for the first time, NiFe₂O₄@ZnMn₂O₄ magnetic nanocomposites (MNCs) were synthesized using a simple green sol–gel method. The synthesized nanocomposites comprehensive characterized using various analytical techniques including X-ray Photoelectron Spectroscopy, powder X-ray diffraction (XRD), transmission electron microscope, field emission scanning electron microscopy, energy dispersive X-ray analysis, vibrating sample magnetometer, Brunauer Emmett Teller, and elemental mapping. XRD confirmed the spinel crystal structure of NiFe₂O₄@ZnMn₂O₄ MNCs. ZnMn₂O₄ has tetragonal spinel structure while NiFe₂O₄ cubic. In microwave-assisted tetrahydropyrimidine and polyhydroquinoline derivative production, NiFe₂O₄@ZnMn₂O₄ MNCs showed good catalytic activity. An external magnet can remove catalyst from reactions, and their efficacy stays stable after four cycles.