Organic electroluminescent materials and devices

is provided. In the structure of Formula I, each one of X1 to X16 is independently CRX or N; each RX and R are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene, azadibenzofuran, azadibenzothiophene, azadibenzoselenophene, triphenylene, azatriphenylene, and combinations thereof; and any adjacent RX can join to form fused or unfused rings. Formulations and devices, such as an OLEDs, that include the compound containing a structure of Formula I are also described.