In an effort to design new functionalized nanostructures for clean energy storage, DFT calculations of Fe-n (n = 1-3) clusters on BC3 and BN monolayers are performed. The stability of the systems was considered by calculating the binding energies of the monolayers with Fe-n clusters on one or both sides. All the clusters bound strongly to both the monolayers and transferred electron density to the sheets. The cationic Fe clusters were then able to adsorb multiple H-2 molecules through electrostatic and van der Waals interactions. The average adsorption energies per H-2 in the case of maximum coverage were calculated to, be -0.389 and -0.358 eV for systems with one Fe on both sides of BC3 and BN monolayers, respectively. In these cases four H-2 molecules were adsorbed to the Fe atoms on both sides of the monolayer. These adsorption energies are such that there is potential for adsorption/desorption at ambient conditions. The results provide insights into an efficient and reversible storage of H-2 by using Fe-n- functionalized BC3 and BN monolayers.