The clean access to 2 as a rare base-free, room-temperature stable and highly soluble divalent lanthanide complex gave us the opportunity to study its reactivity towards industrially relevant small molecules, such as H 2 , which usually does not bind strongly with f-elements. Herein, its coordination to the lanthanide center in 2 would not suffer from the presence of a better ligand. Due to its unique properties, 2 reacts with H 2 under very smooth conditions (1.2-1.5 bar of H 2 , ambient temperature), leading to quantitative conversion into the hydride complex 3-H over the course of 1-3 days (Figure ). Reaction with D 2 proceeded similarly, yielding the Lu III deuteride 3-D, without any appreciable deuteration of the ligand backbone. It should be stressed that the reactivity of 2 with H 2 is much faster than its thermal decomposition into 3-H and 4 (see Figure ), meaning that another direct pathway must be active to form 3-H (see below for mechanistic insights by DFT calculations).