Ir-catalyzed (20 degrees C) or thermal (70 degrees C) dehydrocoupling of the linear diborazane MeNH(2)-BH(2)-NHMe-BH(3) led to the formation of poly- or oligoamino-boranes [MeNH-BH(2)](x) (x = 3 to > 1000) via an initial redistribution process that forms MeNH(2)center dot BH(3) and also transient MeNH=BH(2), which exists in the predominantly metal-bound and free forms, respectively. Studies of analogous chemistry led to the discovery of metal-free hydrogenation of the B=N bond in the "model" aminoborane iPr(2)N=BH(2) to give iPr(2)NH center dot BH(3) upon treatment with the diborazane Me(3)N-BH(2)-NHMe-BH(3) or amine-boranes RR'NH center dot BH(3) (R, R' = H or Me).