We apply our theoretical and computational expertise to the rational design and characterisation of functional molecules and materials for energy, health, sustainability and advanced molecular technologies. We study how structure, reactivity and function connect, using quantum chemical and multiscale modelling tools to predict properties, guide synthetic targets and support experimental collaboration. A major part of this work focuses on main-group chemistry, particularly boron-based systems, whose electronic structure enables diverse reactivity and unconventional bonding motifs. We investigate N-heterocyclic carbenes (NHCs) and related ligands as stabilising platforms for low-valent main-group species, giving access to compounds with unusual oxidation states, non-classical bonding patterns and distinctive reactivities. These species create opportunities for metal-free catalysis, small-molecule activation and bond-activation processes that can complement or rival transition-metal chemistry. Our group also contributes to the computational development of bioactive molecules, including systems relevant to neglected tropical diseases, by evaluating structure–activity relationships, predicting photophysical behaviour for bioimaging agents and optimising molecular scaffolds for efficacy and biocompatibility, with close alignment to the UN Sustainable Development Goals. Through these efforts, we connect fundamental theory with applications and support the design of next-generation molecules and materials.