In summary, we have demonstrated the extensive effect of macroligand sites on the catalytic performance of immobilized Ru species. The Ru-loaded polyphosphines, derived from the crosslinking of PPh3 units, exhibited similar catalytic performances in the CO2 hydrogenation to formate, regardless of the compared synthesis pathways. In the immobilization approach, labile monodentate ligands of the metal precursor promote the ligand exchange with the fixed coordination sites, resulting in active heterogenized catalysts. The analysis of the catalytic system revealed that NaHCO3 enhances the hydrogenation reaction, suggesting its role as deprotonating base and actual substrate, while the kinetics are mainly dependent on the H2 partial pressure.