Composition of matter for use in organic light-emitting diodes

A compound of Formula (I):

• wherein
• D is independently selected from
• XD is independently selected from O, S, NRD′, C(O), substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted vinylene, substituted or unsubstituted o-arylene, and substituted or unsubstituted o-heteroarylene;
• wherein each instance of methylene, ethylene, vinylene, o-arylene or o-heteroarylene can be substituted with one or more substituents independently selected from deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl;
• two or more instances of XD taken together can form a ring system;
• RD is independently selected from hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted amino, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaryloxy, and silyl;
• two or more instances of RD taken together can form a ring system;
• RD′ is independently selected from hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted amino, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl;
• two or more instances of RD′ and RD taken together can form a ring system;
• LD is independently selected from single bond, substituted or unsubstituted arylene, and substituted or unsubstituted heteroarylene;
• wherein each instance of arylene and heteroarylene can be substituted with one or more substituents independently selected from deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl;
• two or more of these substituents taken together can form a ring system;
• Ar is independently substituted or unsubstituted aryl, wherein each instance of aryl can be substituted with one or more substituents independently selected from deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl;
• two or more of these substituents are not taken together to form a ring system;
• Z is CR;
• R is D;
• k is 1;
• m is 2 or 3;
• n is 1 or 2;
• (k+m+n) is less than or equal to 5;
• and
• each “*” represents a point of attachment to Formula (I).