<p>Ligand design has garnered significant attention in catalytic reaction development. This study reports the synthesis of novel polyazo ligands and their application in heterogeneous catalysis for the efficient and sustainable synthesis of diverse organic compounds. A novel pyrimidinyl pyrazole-based porous organic polymer was designed and synthesized. The resulting corresponding manganese composite PME@Mn was subsequently prepared and evaluated for its catalytic activity in the synthesis of quinazolinones and triazine derivatives through the acceptorless dehydrogenation coupling. It was disclosed that PME@Mn catalytic system exhibited quite broad substrate scope and high stability. In addition, this PME@Mn catalyst could be recycled and reused without a manifest loss of catalytic activity for at least five times and revealed potential application value.</p> Graphical Abstract <p></p>