Organic electroluminescent materials and devices

An organic light emitting device (OLED) comprising:

• an anode;
• a cathode;
• and
• an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a compound comprising a tetradentate ligand, LA, wherein:
• LA is coordinated to a metal M, which is selected from the group consisting of Pt, Pd, Cu, Ag, and Au;
• LA comprises a first moiety and a second moiety;
• the first and the second moieties are both coordinated to the metal M;
• the first moiety and the second moiety are different from one another;
• the first moiety is a heterocyclic carbene, which coordinates to the metal M through a metal-carbene bond;
• the second moiety is a 5-membered heterocycle;
• ligand LA forms at least one M-K bond;
• and
• K is a bivalent O or S;
• with the proviso that:
• 1) the compound does not comprise a moiety,
• wherein K′ is selected from the group consisting of a direct bond, O, and S, and Y is selected from the group consisting of NR, O, S, and Se;
• and
• 2) when the compound comprises two M-O bonds, then the first moiety is not an N-heterocyclic carbene.

A consumer product comprising an organic light-emitting device comprising:

• an anode;
• a cathode;
• and
• an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a compound comprising a tetradentate ligand, LA, wherein:
• LA is coordinated to a metal M, which is selected from the group consisting of Pt, Pd, Cu, Ag, and Au;
• LA comprises a first moiety and a second moiety;
• the first and the second moieties are both coordinated to the metal M;
• the first moiety and the second moiety are different from one another;
• the first moiety is a heterocyclic carbene, which coordinates to the metal M through a metal-carbene bond;
• the second moiety is a 5-membered heterocycle;
• ligand LA forms at least one M-K bond;
• and
• K is a bivalent O or S;
• with the proviso that:
• 1) the compound does not comprise a moiety,
• wherein K′ is selected from the group consisting of a direct bond, O, and S, and Y is selected from the group consisting of NR, O, S, and Se;
• and
• 2) when the compound comprises two M-O bonds, then the first moiety is not an N-heterocyclic carbene.