New oxyquinoline boron complexes Mes₂BQ (I) and Mes₂BQ^Me (II), where QH is 8-hydroxyquinoline and Q^MeH is 2-methyl-8-hydroxyquinoline, (CIF files CCDC 1051351 (I) and 1051352 (II)) are synthesized and structurally characterized. Their photoluminescence (PL) and electroluminescence (EL) properties are studied. The compounds have an intense green PL. The EL characteristics of complexes I and II doped in poly-N-vinylcarbazole (PVK) differ substantially. Compound I generates green luminescence with a brightness of 356 cd/m2, whereas white EL with a brightness of 36 cd/m² is observed in the case of compound II.