Organic electroluminescent materials and devices

A compound having a structure of B(A)2, wherein A has a structure of Formula 1:

• wherein,
• X is, at each occurrence identically or differently, selected from the group consisting of O, S, Se, NR′ and CR″R′″;
• Y is, at each occurrence identically or differently, selected from the group consisting of CRY and N;
• W is, at each occurrence identically or differently, selected from the group consisting of O, S, Se and NRN;
• wherein, B is selected from a substituted or unsubstituted conjugated unsaturated fused aryl ring having 10 to 30 ring atoms, or a substituted or unsubstituted conjugated unsaturated fused heteroaryl ring having 10 to 30 ring atoms, or selected from the structure represented by one of Formula 2 to Formula 8, or combinations thereof:
• wherein B is fused with each of A through a single bond and a double bond;
• wherein Z is, at each occurrence, identically or differently, selected from the group consisting of CR and N;
• n is, at each occurrence, identically or differently, selected from 0, 1, or 2;
• wherein, R, R′, R″, R′″, RN and RY are, at each occurrence, identically or differently, selected from the group consisting of hydrogen, deuterium, halogen, nitroso, nitro, acyl, carbonyl, a carboxylic acid group, an ester group, cyano, isocyano, SCN, OCN, SF5, boranyl, sulfinyl, sulfonyl, phosphoroso, sulfanyl, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 20 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 20 carbon atoms, and combinations thereof;
• wherein at least one of R, R′, R″, R′″, RN and RY is a group having at least one electron-withdrawing group;
• any two adjacent substituents R, R′, R″, R′″, RN and RY can be optionally joined to form a ring;
• wherein, when B is selected form Formula 2 or Formula 3, and all of Y are CRY, X is, at each occurrence identically or differently, selected from the group consisting of S, Se, NR′ and CR″R′″.