A series of pentaaryl-substituted diazaboroles have been prepared for the first time by a novel strategy based on the C-C double bond formation from imidoylstannane reagents in the presence of dibromo-phenylboranes. The aryl substituents on the 4,5-position of the planar C2N2B core have substantial effects on their electronic structures. All the new diazaboroles are luminescent both in solution and in the solid state. DFT calculations indicate the 4,5-C-aryl substituents have significant contributions to the LUMOs.