The bond activation chemistry of B(C₆F₅)₃ and related electron-deficient boranes is currently experiencing a renaissance due to the fascinating development of frustrated Lewis pairs (FLPs). B(C₆F₅)₃'s ability to catalytically activate Si–H bonds through η¹ coordination opened the door to several unique reduction processes. The ground-breaking finding that the same family of fully or partially fluorinated boron Lewis acids allows for the related H–H bond activation, either alone or as a component of an FLP, brought considerable momentum into the area of transition-metal-free hydrogenation and, likewise, hydrosilylation. This review comprehensively summarises synthetic methods involving borane-catalysed Si–H and H–H bond activation. Systems corresponding to an FLP-type situation are not covered. Aside from the broad manifold of CX bond reductions and CX/C–X defunctionalisations, dehydrogenative (oxidative) Si–H couplings are also included.