Main-group compounds capable of mimicking transition-metal reactivity in the activation of small molecules, such as dihydrogen, attract much interest of the scientific community due to their potential to serve as alternatives to noble transition-metal catalysts . The basic principle for the design of main-group compounds capable of activating small molecules is that they have to possess a high-lying highest occupied molecular orbital (HOMO) and a low-lying lowest unoccupied molecular orbital (LUMO). This can be achieved at a single main-group center in certain low-valent compounds such as carbenes , borylenes and their heavier analogs . Alternatively, two main-group centers in which one center is a strong Lewis base (high HOMO) and the other is a strong Lewis acid (low LUMO) known as frustrated Lewis pairs (FLPs) were also shown to activate small molecules between these two centers . Recently, the activation of small molecules by phosphorus-based species gained a lot of attention due to their ability to cycle between two stable oxidation states P III and P V . The strategy to obtain an ambiphilic (both nucleophilic and electrophilic) P III -center, which can activate small molecules, is to geometrically constrain it by a rigid pincer-type ligand . This constraint causes the rehybridization of the molecular orbitals (MO) at P-center and as a result a decrease in the HOMO-LUMO gap . Ambiphilic, geometrically constrained P III -centers were shown to activate O-H , N-H (21-23), Ar-F (24-25) and Si-H (26) bonds by their formal oxidative addition, producing new P V species. In some cases, these activation processes were reversible and the initial P III compounds could be obtained back as a result of the reductive elimination type reaction . Despite recent progress in the activation of small molecules at the ambiphilic P III -centers, a highly desirable activation of H-H bond by a formal oxidative addition to P III -center was never reported to the best of our knowledge. Noteworthy, only recently the first example of the oxidative addition of H2 to transient stibinidene, generated from distibene, was reported , which up to date is the only Group 15 based molecular center capable of such reactivity. Although, dehydrogenation of ammonia-borane (H3NBH3) by an ambiphilic P III -center producing dihydridophosphorane (P V ) and catalytic transfer hydrogenation to azobenzene was reported . Furthermore, while the activation of H-H bond by the ambiphilic single main-group centers is known , catalytic hydrogenation using these species was never reported.