Well-defined iron bis(diphosphine) complexes are active catalysts for the dehydrogenativeC-Hborylation of aromatic and heteroaromatic derivatives with pinacolborane. The corresponding borylated compounds were isolated in moderate to good yields (25-73%) with a 5 mol% catalyst loading under UV irradiation (350 nm) at roomtemperature. Stoichiometric reactivity studies and isolation of an original tran