Using the first-principles density functional theory approach, a detailed gas phase dehydrogenation analysis has been carried out for the monomeric as well as the dimeric units of lithium hydrazinidoborane (LiN2H3BH3). Atoms in molecules formalism (AIM) has been employed in order to get bonding features along the desired reaction pathways. The exploration of potential energy surfaces from different structural isomers of both monomeric and dimeric hydrazinidoborane (LiHB) suggests that all the dehydrogenation reactions are endothermic in nature. Hydrogen generation from the dimeric lithium hydrazinidoborane provides an idea about the effect of neighbouring molecules on the dehydrogenation process occurring in the solid state. The lithium ion plays the central role in transferring the hydride in the dehydrogenation of both the monomeric and dimeric form of hydrazinidoborane. In summary our theoretical calculations are expected to shed light on the decomposition mechanism of alkali metal substituted hydrazine-borane type of compounds. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.