Hydrazone‐Based Robust Porous Organic Polymer as a Heterogeneous Hydrogen‐Bond Donor Organocatalyst for the Cascade‐Type One‐Pot Synthesis of Tetrahydrobenzo[ b ]pyrans

In this work, we present the synthesis of NBH‐POP, a novel hydrazone‐based porous organic polymer synthesized using a straightforward solvothermal condensation technique. A well‐organized porous structure, a high density of hydrazone linkages that produce a large number of active sites for substrate adsorption and activation, and exceptional chemical and thermal stability are all features of the material. A thorough characterization utilizing solid‐state 13 C CP‐MAS NMR, FTIR, PXRD, BET, TGA, FE‐SEM, HR‐TEM, and BET verified the successful formation of a semi‐crystalline resilient structure. Owing to the intrinsic hydrogen‐bond donor (HBD) sites, NBH‐POP functions as an efficient metal‐free organocatalyst in the one‐pot Knoevenagel‐Michael cascade reaction, affording excellent yields under mild and green conditions. Importantly, the catalyst retained its structural integrity and activity over multiple recycling cycles, highlighting its robustness and reusability. Overall, these findings establish NBH‐POP as a promising, sustained, and highly efficient heterogeneous organo‐catalyst for green multicomponent synthesis of tetrahydrobenzo[b]pyrans.