Provided are compounds comprising a first ligand L.sub.A; wherein L.sub.A comprises a 5-membered heterocycle joined to a metal M by a M-C or M-N bond; wherein the 5-membered heterocycle comprises at least one boron atom; wherein M is selected from the group consisting of Os, Ir, Pd, Pt, Cu, Ag, and Au; and wherein L.sub.A does not comprise a structure of Formula I.

##STR00001##

wherein X is B or N; with the proviso that the 5-membered heterocycle does not comprise a B—B bond; and with the proviso that if M is Pd or Pt and the 5-membered heterocycle is fused to a benzene ring, the benzene ring is not part of a 6-membered chelate ring comprising M. Also provided are formulations comprising these compounds. Further provided are OLEDs and related consumer products that utilize these compounds.

A composition including a first compound represented by Formula 1 and a second compound represented by Formula 2:

##STR00001##

wherein in Formula 1, M.sub.1 is Pt, Pd, or Au, in Formula 2, M.sub.2 is Ir, L.sub.11 is a ligand represented by Formula 2-1, L.sub.12 is a ligand represented by Formula 2-2, L.sub.13 is a ligand represented by Formula 2-1 or 2-2, L.sub.11 and L.sub.12 are different from each other, n11, n12, and n13 are each independently 0, 1, 2, or 3, and a sum of n11+n12+n13 is equal to 3, and wherein the remaining substituent groups are each understood by referring to the detailed description provided herein.

An organometallic compound represented by Formula 1 emits deep blue light. A light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device may have excellent or suitable driving voltage, luminescence efficiency, color conversion efficiency, and/or lifespan characteristics:

##STR00001##

In Formula 1, X.sub.1 to X.sub.4 are each independently C or N, Y.sub.11 is C(Z.sub.11) or N, and Y.sub.12 is C(Z.sub.12) or N.

An organic electroluminescent device having high efficiency and high driving stability, and a material suitable for the organic electroluminescent device are provided. The material for organic electroluminescent devices comprises an indolocarbazole compound represented by a general formula (1). In the formula, the ring a is represented by a formula (1a), X is NR, S, O or CR.sub.2, and Ar.sup.1 and Ar.sup.2 are an aromatic heterocyclic group represented by a formula (1b). Y is N or CR, and at least one is N. L.sup.1 is an aromatic hydrocarbon group. The material for the organic electroluminescent devices is suitable as material for the host of the light emitting layer or the hole blocking layer of organic EL devices.

##STR00001##

An organometallic compound is represented by Formula 1. A light-emitting device includes a first electrode, a second electrode facing the first electrode, an interlayer disposed between the first electrode and the second electrode and including an emission layer, and at least one organometallic compound represented by Formula 1. An electronic apparatus includes the light-emitting device.

A compound of Formula I,

##STR00001##

is disclosed. In Formula I, M is Pd or Pt; each of X.sup.1 to X.sup.12 is C or N; each of X.sup.13 and X.sup.14 is CH, CD or N; each of Z.sup.1, Z.sup.2, and Z.sup.3 is C or N; L.sup.1 is selected from a variety of bivalent linkers; X is selected from O, S, Se, NR′, and CR″R′″; each R, R′, R.sup.1, R.sup.2, R.sup.3, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E is hydrogen or a General Substituent; at least one of Z.sup.1, Z.sup.2, and Z.sup.3 is a carbon atom substituted with a substituent with a molecular weight of at least 16. Formulations, OLEDs, and consumer products that include Formula I are also disclosed.

Disclosed herein are a novel organometallic compound and an organic light-emitting diode including same. More specifically, an organometallic compound represented by [Chemical Formula 1] and an organic light-emitting diode including same are provided.

Provided is an organometallic complex including a ligand L.sub.A having a structure represented by one of the following formulas ##STR00001##
and coordiated to Ir.

Platinum, palladium, and gold tetradentate metal complexes of Formulas I and II including indoloacridine.

##STR00001##

The complexes are suitable for use as phosphorescent or delayed fluorescent and phosphorescent emitters in display and lighting applications.

Metal-assisted delayed fluorescent (MADF) emitters including cyclic tetradentate platinum (II) and palladium (II) complexes employing 8H-pyrido[3′,2′:4,5]-pyrrolo[3,2,1-de]acridine and its analogues. These complexes provide improved color purity and enhanced operational stability and are suitable for luminescent labels, emitters for organic light emitting diodes (OLEDs), and lighting applications.