NOVELTY - Fluorene derivatives (Q) (I), (II), (IIIa) or (IIIb), are new.    USE - (I), (II), (IIIa) or (IIIb) are useful in an emission layer, preferably as a matrix material for phosphorescent emitter or in an electron transport layer, in an organic electroluminescent device, an organic integrated circuit, an organic field-effect transistor, an organic thin film transistor, an organic light-emitting transistor, an organic solar cell, an organic optical detector, an organic photoreceptor, an organic field-quench device, a light-emitting electrochemical cell or an organic laser diode (all claimed).    ADVANTAGE - (I), (II), (IIIa) or (IIIb) produces organic electroluminescent device with high quantum efficiency, long service life and low operating voltage.    DETAILED DESCRIPTION - Fluorene derivatives (Q) of formulae (I), (II), (IIIa) or (IIIb), are new.    Ar3 = triazine, pyrazine, pyrimidine, pyridazine, pyridine, pyrazole, imidazole, oxazole, 1,3,4-oxadiazole, benzimidazole or thiazole (each of which is substituted with R1);    X = fluorine derivative of formula (IV), bivalent bridge comprising B(Ar2), C=C(Ar2)2 or C=NAR2;    b = bonding to the two benzene rings;    X1 = bivalent bridge comprising B(R1), C(R1)2, Si(R1)2, C=C(R1)2), C=NR1, B(Ar1), C(Ar1)2, Si(Ar1)2, C=C(Ar1)2 or C=NAr1; either    R1 = H, D, F, Cl, Br, I, CHO, N(Ar1)2, C(=O)Ar1, P(=O)(Ar1)2, S(=O)Ar1, S(=O)2Ar1, CR2=CR2Ar1, CN, NO2, Si(R2)3, B(OR2)2, B(R2)2, B(N(R2)2), OSO2R2, 1-40C alkyl, 1-40C alkoxy, 1-40C thioalkoxy, 2-40C alkenyl, 2-40C alkynyl, branched or cyclic 3-40C alkyl, 3-40C alkenyl, 3-40C alkynyl, 3-40C alkoxy or 3-40C thioalkoxy (where each one is substituted with R2 and non-adjacent CH2 are replaced by R2C=CR2, C=C, Si(R2)2, Ge(R2)2, Sn(R2)2, C=O, C=S, C=Se, C=NR2, P(=O)(R2)SO, SO2, NR2, O, S or CONR2, H is replaced by D, F, Cl, Br, I, CN or NO2) or aromatic or heteroaromatic ring system with 5-60 aromatic ring atoms, aryloxy or heteroaryloxy with 5-60 aromatic ring atoms, aralkyl or heteroaralkyl with 5-60 aromatic ring atoms (each of which is substituted by R2); or    2R1 = mono-, polycyclic, aliphatic or aromatic ring system;    Ar1 = aromatic or heteroaromatic ring system with 5-30 aromatic ring atoms (where each one is substituted with R2, and two radicals Ar1, which are bound to same N, P or B are linked together by single bond or bridge comprising B(R2), C(R2)2, Si(R2)2, C=O, C=NR2, C=C(R2)2, O, S, S=O, SO2, N(R2), P(R2) or P(=O)R2; either    R2 = H, D, aliphatic, aromatic, heterocyclic 1-20C aromatic organic group, where H is replaced by D or F; or    2R2 = mono-, polycyclic, aliphatic or aromatic ring system;    n = 0 or 1;    m = 0-3; either    o = 0-3 (when m is 0) or    o = 0-3 (when m is 2); either    p, q = 0 or 1; or    p+q = 1 or 2; and    Ar2 = carbazole, azacarbazole, cis- or trans-indenocarbazole, cis- or trans-indeno-azacarbazole, or cis-or trans-indolocarbazole, where each one is substituted with R1, and adjacent substituents R1 together with the atoms to which they are attached form mono-, polycyclic, aliphatic or aromatic ring system.    Provided that: Ar2 is not in conjugation with Ar3. INDEPENDENT CLAIMS are also included for:    (1) producing (I), (II), (IIIa), or (IIIb;    (2) a mixture comprising at least one phosphorescent emitter and at least one of (I), (II), (IIIa) or (IIIb); and    (3) a solution or a formulation comprising at least one of (I), (II), (IIIa), (IIIb), at least one solvent, preferably an organic solvent.