| abstract |
Formula D, wherein X is selected from NRN, O, S, or Se; and RN is selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl, and combinations thereof; and Y1, Y2, Y3, and Y4 are independently CRY1, CRY2, CRY3, and CRY4, respectively, or N, and Ring D has no more than two nitrogen ring atoms. An OLED that includes a compound of the Formula I above in an organic layer is also described. |