Boron is a unique element in its extreme tendency to form both covalent, and delocalized chemical bonds. It is a small atom, similar to C in many ways, and yet with electronegativity similar to such transition metals as Pt. The chemistry of B therefore keeps brining new surprises. We will show how all-B clusters have unusual, flat shapes, how the electronic structure of these clusters can be exploited to create cluster motors, and how B completely changed the shape and properties of metal clusters. It will be demonstrated how B-metal interactions then can be harvested in the design of new catalysts resistant to deactivation, as well as interesting surface alloys and new 2D materials. Finally, B-metal interactions lead to the formation of ultra-hard materials that can scratch diamond. All these findings come from exploiting the electronic structure in a strategic way, and in close collaboration between theory and experiment.