In the present work, the behavior of hydrazine borane N2H4BH3 in the presence of alkali/alkaline-earth hydrides is investigated. (i) Hydrazine borane N2H4BH3 is readily destabilized by an alkali hydride MH (M=Li, Na, K). The electronic properties of M drive the reactivity of MH1 towards N2H4BH3. KH is the most reactive (at 25 degrees C, Delta H-r = -70.25 kJ mol(-1)) while K is the least electronegative and the biggest element. Hydrazinidoboranes MN2H3BH3 form. (ii) Hydrazine borane N2H4BH3 is destabilized by MHx (x = 2, 3; M=Mg, Ca, Al). In comparison to pristine N2H4BH3, better dehydrogenation properties are found: MgH2 has a catalytic effect; CaH2 strongly destabilizes N2H4BH3; and, unstable AlH3 is able to destabilize N2H4BH3 under heating. Though the synthesis of hydrazinidoboranes M(N2H3BH3)(x), is difficult, the mixtures MHx-N2H4BH3 leads to composites. The most efficient composite is CaH2-N2H4BH3. The aforementioned hydrazinidoboranes and composites may have potential as solid-state hydrogen storage materials. This is discussed herein. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.