Organic electroluminescent materials and devices

A compound of formula Ir(LA)2LC;

• wherein:
• each ligand LA can be the same or different and has Formula I
• each LA is coordinated to Ir to give a 5-membered chelate;
• A1 is a multicyclic fused ring system comprising two or more fused 5-membered or 6-membered carbocyclic or heterocyclic rings;
• A2 is a 5-membered heterocyclic ring or a multicyclic fused ring system comprising at least one 5-membered heterocyclic ring which is coordinated to Ir and one or more 5-membered or 6-membered carbocyclic or heterocyclic rings;
• with the proviso that A1 doesn't fuse into A2;
• LC has the structure of Formula II
• each RA, RB, Ra1, Rb1 and Rc1 is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, germyl, boryl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof;
• with the proviso that Ra1 and Rc1 are not both isobutyl when Rb1 is H,
• any two adjacent RA, RB, Ra1, Rb1 and Rc1 in the compound can be joined or fused together to form a ring;
• and
• if two RA are joined to form a ring when LA has the structure
• said ring is a 5- or 6-membered ring.