We report the synthesis of structurally tunable boron complexes supported by N-heterocyclic imine ligands IPr=N-BR (IPr=[(HCNDipp) C], Dipp=2,6-iPr C H , R=Cl and/or Ph) that have the ability to abstract dihydrogen from amine-boranes, and instigate their dehydrocoupling. In one instance, mild heating of the hydrogen addition product IPr=NH-B(Ph)HCl releases H to regenerate the starting N-heterocyclic iminoborane; accordingly IPr=N-B(Ph)Cl can be used as a metal-free catalyst to promote the dehydrocoupling of MeNH ⋅BH to yield N-methylaminoborane oligomers [MeNH-BH ] .