Catalytic hydrogenation reactions have many important applications in the synthesis of chemicals, pharmaceuticals, and fuels. However, currently most catalytic hydrogenation systems rely on catalysts that contain rare and precious late transition metals. [Fe]-hydrogenase is an enzyme considered as an efficient catalyst for hydrogenation reactions. Though various Fe-based synthetic mimics of the active site of [Fe]-hydrogenase have been synthesized, only one of them was reported to activate H2. Recent studies have revealed the great potential of Mn as hydrogenation catalysts. Here we propose to combine the active site of [Fe]-hydrogenase with Mn metal and develop a novel class of Mn complexes. Complex design and synthesis, structure-function study, hydrogenation methodology development and reconstitution of [Mn]-hydrogenase for biochemistry study are the main objectives of this proposal. This work will result in not only new fundamental understanding of base metal catalysis, but also industrially relevant catalysts.