Organic electroluminescent materials and devices

A compound having Formula 1:

• wherein
• X1, X2, X3, and X4 are each independently selected from the group consisting of CR, and N;
• when X1, X2, X3, and X4 are each independently selected from CR, each R may be same or different, and at least one of R comprises at least one electron withdrawing group;
• Z1 and Z2 are each independently selected from the group consisting of O, S, Se, S═O, and SO2;
• X and Y are each independently selected from the group consisting of S, Se, NR′, and CR″R′″;
• R, R′, R″, and R′″ are each independently selected from the group consisting of hydrogen, deuterium, halogen, 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 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, a substituted or unsubstituted amino group having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a nitrile group, an isonitrile group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group, and combinations thereof;
• Any adjacent substitution can be optionally joined to form a ring or fused structure.