This work reports the synthesis and characterization of ruthenium nanoparticles (Ru NPs) supported on polymeric ionic liquids (PILs). This catalyst shows high catalytic activity towards the N‐formylation of amines and synthesis of benzimidazoles from 1,2 diamines and carbon dioxide (CO2) by reductive dehydrogenation of dimethylamine borane. This methodology shows excellent functional group tolerance with broad substrate scope towards the synthesis of N‐formamides and benzimidazoles. Interestingly, this protocol also provides the tandem reduction of 2‐nitroamines and CO2 to synthesize benzimidazoles. It was proposed that the ionic liquid phase of polymer plays pivotal roles such as assisting the stabilization of nanoparticles electrostatically, providing the ionic environment and controlling the easy access of the substrates/reagents to the active sites. The developed methodology utilizes the CO2 as C1 source and water: ethanol as green solvents system. Additionally, the catalyst was found to recyclable in nature and shows five consecutive recycle runs without significant loss in its activity.