A compound of Formula I:






wherein ring A is a 5-membered or 6-membered aromatic ring;
wherein RA, RB, and RC each independently represent mono to the maximum allowable substitution, or no substitution;
wherein Y1 is absent or present, and when present is selected from the group consisting of a direct bond, O, S, Se, CRR′, NR, SiRR′, and BR;
wherein each X1-X3 is N or CR;
wherein at least one of X1-X3 is N;
wherein each A1-A5 is independently C or N;
wherein the maximum number of N atoms that can connect to each other within each ring is two;
wherein each R1, R2, R3, and R4 is independently selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, heteroaryl, and combinations thereof;
wherein each R, R′, RA, RB, and RC is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and
wherein any two substituents may be joined or fused together to form a ring.