This Chapter summaries the studies conducted on the reduction of multiple-bonded organic compounds in the presence of NHCâ metal complexes as homogeneous catalysts. The following reactions have been examined: hydrogenation, transfer hydrogenation, hydrosilylation and hydroboration. Reports of the application of hydrosilylation and hydroboration in the synthesis of complex organic molecules and via subsequent cleavage of Siâ C or Bâ C bonds are also discussed.