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 [B12H12](2-), monocarborane [CB11H12](1-), dicarborane [C2B10H12], and closo-azaborane [NB11H12] cages is almost similar (similar to 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 [C2Al10H12] 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. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.