Heterogeneous catalysis is one of the fastest and greatest developing branches and longstanding challenges in academic researchers and the chemical industry. Carbon-based material with various functional groups, the most abundant elements, and the main component in natural products provide a unique platform for heterogeneous catalysis due to their excellent biocompatibility and high performance. Herein, we introduce a novel nanocomposite comprising of different acids anchored to magnetic mesoporous carbon nitrides through a grindstone method to enhance nanocomposite catalysts’ environmentally benign capability. As a result, the obtained porous magnetic catalysts show the highest possible activity and product selectivity for facile preparation of α-amino phosphonates derivatives in good to excellent yields at ambient temperature. This fast and straightforward methodology offers pot economy for the satisfactory reaction of various aldehyde, amine, and triaryl and trialkyl phosphite with a broad range of functional groups in a gram scale under mild reaction conditions.