Display omitted •The first application of the Pd(2-pymo)2n framework in hydrogen production from NH3BH3.•Selective transfer hydrogenation of phenylacetylene with NH3BH3 in water.•Evidence for the contribution of water as a hydrogen donor in the transfer hydrogenation. The Pd(2-pymo)2n (2-pymo = 2-pyrimidinolate) framework catalyses the conversion of NH3BH3 to H2 in water. Independently of the amount of NH3BH3, ca. two equivalents of H2 were formed, most probably due to the presence of hydrophobic windows in the MOF structure. The introduction of styrene or phenylacetylene into the system, stopped H2 production. Instead, hydrogen transfer hydrogenation occurred. Mechanistic studies, performed with deuterated substrates, evidenced that water used as a solvent is also a hydrogen donor and contributed to the hydrogenation of styrene and phenylacetylene.