In this research work, we have investigated the crystal structure, thermodynamic and electronic properties to elucidate the chemical bonding features of N2H4BH3 and MN2H3BH3 (M = Na and K), using both plane waves and pseudopotentiels methods applied in density functional theory. The as-optimized crystal structures are found to be in a good agreement with the experimental. The bond lengths of these materials have been compared to show the effect of alkali metal (Na and K) in N2H4BH3. The density of states (DOS) indicated that these materials are considered as an insulator with wide band-gap: 5.78, 4.35 and 4.36 eV for N2H4BH3, NaN2H3BH3 and KN2H3BH3, respectively. This indicated that the substitution of one hydrogen atom from N2H4BH3 by alkali atom (Na or K) could reduce the band-gap. The partial DOS, Hirshfeld method and charge density distribution have been used to understand the nature of the chemical bond. It is found that the chemical bonding in each group namely [N2H4] and [BH3] for N2H4BH3 or [N2H3] and [BH3] for MN2H3BH3 (M = Na and K)) have mainly a covalent nature. While, an ionic character between M (Na and K) and the rest of N2H3BH3 group is suggested for MN2H3BH3 (M = Na and K). Interestingly, both N-H and B-H bonds are destabilized in MN2H3BH3 (M = Na and K) with a less protic character of [BH3] than that of N2H4BH3. Finally, it is observed that each group [BH3] is bonded covalently to another [N2H3] for MN2H3BH3 (M = Na and K) similarly to N2H4BH3 (covalent bonding between [BH3] and [N2H4]). The standard enthalpies of formation of KN2H3BH3 and NaN2H3BH3 are calculated for the first time in this research work. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.