A compound of Formula I ##STR00001##
wherein M is a metal selected from Ir or Os;
rings A, B, C, D, E, and F are independently a 5-membered or 6-membered aromatic ring; Z.sup.1 to Z.sup.14 are independently selected from C or N; X is selected from a direct bond, or a linker with one to ten backbone member atoms; and Y is selected from a direct bond, a linker with one to ten backbone member atoms, or is absent to provide an open hexadentate ligand. An organic electroluminescent device (OLED) that includes an anode, a cathode, and an organic layer comprising a compound of the Formula I, and a consumer product comprising the OLED.

Novel phosphorescent OLED emitters based on metal complexes with indolizine-derived heterocycles as ligands are disclosed. Structural variations of the ligands provide access to a variety of green, yellow and red emitters.

An organic light-emitting device includes: a first electrode; a second electrode; an organic layer between the first electrode and the second electrode and including an emission layer; and at least one organometallic compound represented by Formula 1. The organic light-emitting device including the organometallic compound may have a low driving voltage, a high luminance, a high efficiency, and a long lifespan: ##STR00001##

A compound comprising a first ligand L.sub.A of Formula I,

##STR00001##

is disclosed. In the structure of Formula I, ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring, Z.sup.1-Z.sup.4 are each independently C or N; at least two consecutive Z.sup.1-Z.sup.4 are C, and are fused to a structure of Formula II

##STR00002##

or Formula III

##STR00003##

Y.sup.1 and Y.sup.2 are each independently O, S, Se, CRR′, SiRR′, or GeRR′; each R.sup.A, R.sup.B, R.sup.C, R, and R′ is a hydrogen or a substituent; and any two substituents may be joined or fused together to form a ring. In the compound, L.sub.A is complexed to a metal M by the dashed lines in Formula I to form a five-membered chelate ring, and M has an atomic weight greater than 40. Organic light emitting devices and consumer products containing the compounds are also disclosed.

An organometallic compound represented by Formula 1, which is explained in the specification, is provided. A light-emitting device is provided, which includes a first electrode, a second electrode facing the first electrode, an interlayer between the first electrode and the second electrode and including an emission layer, and the organometallic compound. An electronic apparatus including the light-emitting device is also provided:

##STR00001##

The present invention includes novel heteroleptic/homoleptic iridium complexes containing two tridentate ligands, where at least one of the tridentate ligands comprises of pyridinium-derived N-heterocyclic carbene. The compounds of the present invention may be useful for organic electroluminescent devices.

An organometallic compound represented by Formula 1:
M(L.sub.1).sub.n1(L.sub.2).sub.n2(L.sub.3).sub.n3  Formula 1 wherein in Formula 1, M, L.sub.1, L.sub.2, L.sub.3, n1, n2, and n3 are the same as defined in the specification.

A compound having a first ligand L.sub.A of Formula I ##STR00001##
is disclosed, where Z.sup.1 to Z.sup.4 are each independently C or N; at least one of Z.sup.1 to Z.sup.4 is N; and ring A is a structure of Formula II ##STR00002##

A phosphorescent compound of formula (I): ##STR00001##
wherein: M is a transition metal; C.sup.1 is a carbon atom forming a metal-carbene bond with M; A is a saturated bridged bicyclic or saturated bridged tricyclic group consisting of one nitrogen atom and 6-12 carbon atoms; either: (i) X.sup.1 is a bridgehead carbon atom of the bridged bicyclic or bridged tricyclic group and X.sup.2 is NR.sup.1 wherein R.sup.1 is a substituent, or (ii) X.sup.1 is N and X.sup.2 is a bridgehead group of formula CR.sup.6 wherein R.sup.6 is H or a substituent; Ar.sup.1 is a C.sub.6-20 aromatic group or a 5-20 membered heteroaromatic group; L in each occurrence is independently a mono- or poly-dentate ligand other than a ligand of formula A-Ar.sup.1; x is at least 1; and y is 0 or a positive integer. The compound of formula (I) may be used as a blue light-emitting material in a white organic light-emitting device.

Provided are organometallic compounds having a ligand L.sub.A of Formula I:

##STR00001##

Also provided are formulations including these organometallic compounds. Further provided are OLEDs and related consumer products that utilize these organometallic compounds.