Abstract. The incorporation of main group elements into molecular and polymeric materials is frequently exploited to achieve unusual properties and to enable new functions. For instance, tricoordinate boron’s participation in pi-delocalization can have a dramatic effect on the optical properties by selectively lowering the LUMO orbital levels. The electron-deficient character of boron also enables dynamic Lewis acid-base interactions, which trigger strong perturbations of the electronic structure and enable assembly of novel supramolecular materials. Our group has developed versatile approaches for incorporating borane Lewis acids and Lewis pairs into conjugated molecular, macrocyclic and polymeric materials with a view at potential applications in organic electronics, sensing, (photo)catalysis, bioimaging, and therapeutics. In this talk, I will discuss some of our recent discoveries, highlighting the effect of B-N Lewis pair functionalization on the material properties and the impact in diverse application fields.