NOVELTY - Carbazole-containing compounds (I) are new.    USE - (I) are useful in an organic light emitting device and consumer product (all claimed), where the consumer product is flat panel displays, computer monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads up displays, fully transparent displays, flexible displays, laser printers, telephones, cell phones, personal digital assistants, laptop computers, digital cameras, camcorders, viewfinders, micro-displays, vehicles, and a large area wall, theater or stadium screen, or a sign. (I) are useful in other optoelectronic devices such as organic solar cells and organic photodetectors.    ADVANTAGE - (I) maintains a beneficial high triplet energy and improves charge balance and device stability.    DETAILED DESCRIPTION - Carbazole-containing compounds of formula (I) are new.    a = 1-20;    b = 0-20; either    m, n = 0-2; or    m+n = at least 1;    X = biphenyl, terphenyl, naphthalene, triphenylene, phenanthrene, fluorene, chrysene, dibenzothiophene, dibenzofuran, benzofuran, benzothiophene, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, indole, benzimidazole, indazole, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine or thienodipyridine (all are substituted by R); and    R = H, alkyl, heteroalkyl, benzene, biphenyl, terphenyl, naphthalene, phenalene, phenanthrene, fluorene, chrysene, dibenzothiophene, dibenzofuran, benzofuran, benzothiophene, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, indole, benzimidazole, indazole, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine or thienodipyridine.    INDEPENDENT CLAIMS are included for:    (1) an organic light emitting device, comprising: an anode; a cathode; and a first organic layer disposed between the anode and the cathode, where the organic layer comprises (I);    (2) a consumer product comprising a device, where the device further comprises an anode, a cathode and an organic layer, disposed between the anode and the cathode, where the organic layer further comprises (I); and    (3) a method of fabricating an organic light emitting device, comprising: providing a first electrode; co-depositing a host and a phosphorescent emitter to form an emissive layer, where the emissive layer comprises (I); and depositing a second electrode.