The effects of nanoconfinement on the dehydrogenation rate and reaction pathways of the eutectic LiBH 4 – Mg(BH 4) 2 have been comprehensively investigated. By means of thermal analysis, mass spectroscopy and solid state 11 B MAS NMR, it has been revealed that the multistep thermal decomposition pattern of the binary LiBH 4 –Mg(BH 4) 2 has been altered in a two-step reaction and the desorption kinetics has also been significantly improved after infiltration. The formation of diborane and stable M n B 12 H 12 intermediates of the bulk LiBH 4 –Mg(BH 4) 2 has been found to be inhibited by nanoconfinement.