An organometallic compound including a first ligand L.sub.A selected from

##STR00001## ##STR00002##

is provided. In ligand L.sub.A, each of Y.sup.1 to Y.sup.10 is carbon or nitrogen; moiety B is a monocyclic or polycyclic fused ring structure comprising 5-membered and/or 6-membered rings; any two R.sub.A and R.sub.B can be fused or joined to form a ring; X is selected from O, S, Se, or NR; each R.sub.A and R.sub.B is independently hydrogen or a General Substituent; at least one R, R.sub.A, or R.sub.B is deuterium or a linking group between L.sub.A and another ligand that includes a deuterium substituted aromatic ring; and L.sub.A is coordinated to a metal M, selected from Os, Pd, Pt, Ir, Cu, Ag, or Au; and the compound is capable of emitting light with a peak maximum wavelength (λ.sub.max)≥700 nm at room temperature.

The present disclosure relates to compounds capable of emitting delayed fluorescence, and uses of the compounds in organic light-emitting diodes.

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer, wherein the interlayer includes a heterocyclic compound of Formula 1:

A.sub.1B.sub.1].sub.n1  Formula 1

wherein, in Formula 1, the variables are defined herein.

An organometallic compound represented by Formula 1:

##STR00001##

wherein Ln.sub.1 is a ligand represented by Formula 1A, Ln.sub.2 is a ligand represented by Formula 1B, X.sub.1 is O, S, or Se, CY.sub.1 is a C.sub.5-C.sub.30 carbocyclic group or a C.sub.1-C.sub.30 heterocyclic group, n1 is 1 or 2, n2 is 1, 2, or 3, and the remaining substituents are as defined in the present specification.

A light-emitting device including a heterocyclic compound represented by Formula 1 and a phosphorescent dopant, and an electronic apparatus including the light-emitting device are provided. Formula 1 is the same as described in the present specification. The light-emitting device 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 heterocyclic compound represented by Formula 1.

##STR00001##

A luminescence device, includes: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, wherein the hole transport region includes a compound of Formula 1:

##STR00001##

wherein in the Formula 1, the variables are described herein.

An organic light-emitting device includes a first electrode, a second electrode facing the first electrode, and an organic layer disposed between the first electrode and the second electrode and comprising an emission layer, wherein the compound is of Formula 1, as shown in the equation below: ##STR00001##

An organic light-emitting device includes a first electrode, a second electrode facing the first electrode, and an organic layer disposed between the first electrode and the second electrode and comprising an emission layer, wherein the compound is of Formula 1, as shown in the equation below: ##STR00001##

Provided are compounds comprising anionic bidentate ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications. Also provided are formulations comprising these compounds comprising anionic bidentate ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications. Further provided are OLEDs and related consumer products that utilize these compounds comprising anionic bidentate ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications.

An organic light emitting device including a light emitting layer, which comprises one or more of compounds represented by Formulae 1-1 to 1-3; and a compound represented by Formula 2.

##STR00001## ##STR00002##