NOVELTY - Organic light-emitting diode comprises at least one substituted dibenzofuran or dibenzothiophene compounds (I).    USE - The organic light-emitting diode is useful in devices including stationary visual display units, mobile visual display units, illumination units, keyboards, garments, furniture, wallpaper (all claimed), switching elements, organic transistors, organic solar cells, visual display units of computers, televisions, visual display units in printers, visual display units of kitchen appliances and advertising panels, visual display units of illuminations and information panels, and visual display units of cell phones, laptops, digital cameras, motion picture experts group layer 3 players, vehicles and destination displays on buses and trains.    ADVANTAGE - The organic light-emitting diode has: improved efficiency and operative lifetimes; and high stability to thermal stress with low use and operating voltage.    DETAILED DESCRIPTION - Organic light-emitting diode comprises at least one substituted dibenzofuran or dibenzothiophene compounds of formula (I).    X = S or O;    R1, R2 = aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, crosslinkable or polymerizable group bonded via a spacer, -NR3R4, -P(O)R5R6, -PR7R8, -S(O)2R9, -S(O)R10, -SR11 or OR12 or Z; either    R3, R4 = aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, crosslinkable or polymerizable group bonded via a spacer; or    NR3R4 = cyclyl having 3-10 ring atoms (optionally substituted by at least one alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, group with donor or acceptor action, and/or optionally fused to at least one further cyclyl having 3 to 10 ring atoms, where cyclyl is optionally substituted by at least one alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, crosslinkable or polymerizable group bonded via a spacer, or a group with donor or acceptor action);    R5-R12 = aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, or crosslinkable or polymerizable group bonded via a spacer;    n = 0-4;    m = 0-3;    p = 1 or 2;    m+p = less than or equal to 4;    Z = optionally saturated five-membered heterocyclyl of (II), where Z is bonded in the 2 and/or 4 position, or two units of (I) are bridged to one another via a bond, optionally branched and optionally saturated bridge optionally interrupted by at least one heteroatom or via O, this bridge is bonded in place of R1a, R1b, R1c, R1d, R1e, R1f, R1g, R1h or via and/or in place of R1 or R2, in monomeric, polymerized or crosslinked form; either    R1a-R1h = H, aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, or crosslinkable or polymerizable group bonded via a spacer; or    N(R1a or R1h)(R1c or R1d), N(R1e or R1f)(R1g or R1h) and/or N(R1c or R1d)(R1e or R1f) = cyclyl having 3-10 ring atoms (optionally substituted by at least one alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, crosslinkable or polymerizable group bonded via a spacer, or group with donor or acceptor action, and/or optionally fused to at least one further cyclyl having 3-10 ring atoms, where the fused cyclyl is optionally substituted by at least one alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, crosslinkable or polymerizable group bonded via a spacer, or group with donor or acceptor action);    A1 = CR1a, N or NR1b;    A2 = CR1c, N or NR1d;    A3 = CR1e, N or NR1f; and    A4 = CR1g, N or NR1h.    INDEPENDENT CLAIMS are also included for:    (1) substituted 9H-carbazole compounds of formula (III);    (2) preparing (III) comprises introducing at least one carbazolyl radical of formula (IV) and the optionally substituted five-membered nitrogen heterocyclyl (Z) into a base skeleton of formula (V) according to: (a) preparation of a precursor compound suitable for introduction of the carbazolyl radical(s) (IV), and optionally of the R2 radical(s) and of the Z radical(s), (b) introduction of the carbazolyl radical(s) (IV), (c) introduction of the Z radical(s) or their precursor(s), and, if present, introduction of the R2 radical(s), and (d) optionally, conversion of the precursor of Z to the Z radical; or (e) preparation of a precursor compound suitable for introduction of the carbazolyl radical(s) (IV), and optionally of the R2 radical(s) and of the Z radical(s), (f) introduction of the Z radical(s) or their precursor(a), (g) introduction of the carbazolyl radical(s) (IV), and, if present, introduction of the R2 radical(s), and (h) optionally, conversion of the precursor of Z to the Z radical;    (3) a crosslinked or polymerized material comprising units of (III) or (I);    (4) a formulations for liquid-processed applications in organic electronics comprising (III), (I) or the crosslinked or polymerized material of (III);    (5) an organic electronics comprising (I), (III) or the crosslinked or polymerized material of (III);    (6) an organic light-emitting diode comprising at least one (III) or the crosslinked or polymerized material of (III);    (7) a light-emitting layer comprising at least one (III), (I) or the crosslinked or polymerized material of (III);    (8) a blocking layer for holes/excitons comprising at least one (III), (I) or the crosslinked or polymerized material of (III); and    (9) an electron-conducting layer comprising at least one (III), (I) or the crosslinked or polymerized material of (III).    R22 = aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, crosslinkable or polymerizable group bonded via a spacer, -NR3R4, -P(O)R5R6, -PR7R8, -S(O)2R9, -S(O)R10, -SR11 or OR12, where two units of (III) are bridged to one another via a bond, optionally branched and optionally saturated bridge optionally interrupted by at least one heteroatom or via O, and the bridge is bonded in place of R1a, R1b, R1c, R1d, R1e, R1f, R1g, R1h, R13, R14 or via and/or in place of R22;    R13, R14 = aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, crosslinkable or polymerizable group bonded via a spacer, -NR3R4, -P(O)R5R6, -PR7R8, -S(O)2R9, -S(O)R10, -SR11 or -OR12;    q, r = 0-4; and    s = 1-4.