The hydrogen storage (H-storage) capacity of various boranes and alanes have been investigated using density functional theory (DFT) based M05-2X method employing 6-31+G** basis set. The changes in the H-storage capacities of borane and alane upon substitution of antipodal atoms in the cages by C, Si, and N have also been investigated. It is found from the calculations that a maximum of 20 H 2 molecules can be adsorbed on the deltahedron faces of these cages. The maximum gravimetric density has been observed for boranes when compared to alanes. The H-storage capacity of closo-borane dianion [B 12H 12] 2-, monocarborane [CB 11H 12] 1-, dicarborane [C 2B 10H 12], and closo-azaborane [NB 11H 12] cages is almost similar (∼22 wt.%). Among these cages, B BB dianion show higher binding energy (BE) and BE per H 2 molecule (BE/nH 2) which are 181.06 and 9.03 kJ/mol, respectively. In the case of alanes, dicarbalane [C 2Al 10H 12] has maximum H-storage capacity of 11.6 wt.%. Based on these findings, a new MOF with carborane (MOF-5 CC) as linker has been designed. The calculation on the new MOF-5B CC reveals that it has H-storage capacity of 6.4 wt.% with BE/nH 2 of 3.02 kJ/mol. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.