Novel organic compounds comprising a bicarbazole core are provided. In particular, the compound has a 3;3′-bicarbazole core substituted at the 9th position with at least one of dibenzofuran, dibenzothiophene, dibenzoselenophene, azadibenzofuran, azadibenzothiophene and azadibenzoselenophene. The compounds may be used in organic light emitting devices to provide devices having improved efficiency and improved lifetime.