Do we really need ligands in Ir-catalyzed C–H borylation?

Direct borylation of C–H bonds is a privileged strategy to access versatile building blocks and valuable derivatives of complex molecules (late-stage functionalization, metabolite synthesis). This perspective aims to provide an overview and classification of the catalytic systems developed in this fast-growing area of research. Unexpected selectivity differences between two established directed-borylation systems have been discovered using high-throughput experimentation highlighting the importance of classical control experiments in catalysis research.