The quest for highly active and efficient ligands in coordination polymer-based catalytic applications is paramount. The new porous cross-linked polymer manganese composites, which featured a benzimidazole-pyrimidine backbone, were designed, synthesized and fully characterized through several modern means. The resulting manganese composites revealed good catalytic activity in the selective synthesis of bisindolylmethane derivatives with high selectivity. Furthermore, the porous cross-linked polymer matrix composites displayed impressive recyclability, demonstrating their economic and environmental merits, with mechanistic studies shedding light on these transformative processes.Graphical AbstractThe new porous cross-linked polymer manganese composites, which featured a benzimidazole-pyrimidine backbone. The resulting manganese composites revealed good catalytic activity in the selective synthesis of bisindolylmethane derivatives with high selectivity. Furthermore, the porous cross-linked polymer matrix composites displayed impressive recyclability, demonstrating their economic and environmental merits, with mechanistic studies shedding light on these transformative processes.