NOVELTY - Use of nitrogen-bonded five membered heterocyclic ring substituted dibenzofurans and dibenzothiophenes compounds of formula (I) in monomeric, polymerized or crosslinked form, as host, blocker and/or charge transport materials is claimed.    USE - (I) is useful as host, blocker and/or charge transport material and as electron transport material in organic electronics applications, preferably organic LEDs. (I) and (III) are useful as components in polymerization and/or crosslinking reactions. (III) is useful in formulations for liquid-processed applications in organic electronics. (I) and (III) are useful as matrix material, hole/exciton blocker material, electron/exciton blocker material, hole injection material, electron injection material, hole conductor material, electron conductor material, hole conductor and/or electron conductor, preferably as matrix or electron conductor. (III) or (I) is useful in a light-emitting layer, a blocking layer for holes/excitons, and an electron-conducting layer, which are useful in a device comprising stationary visual display units such as visual display units of computers, televisions, visual display units in printers, kitchen appliances and advertising panels, illuminations, information panels and mobile visual display units, such as visual display units in cell phones, laptops, digital cameras, media player (MP3), vehicles and destination displays on buses and trains; illumination units; keyboards; garments; furniture; wallpaper (all claimed). (I) and (III) are useful in organic electronics applications comprising switching elements such as organic transistors, e.g. organic field-effect transistors and organic thin-film transistors, and organic solar cells.    ADVANTAGE - (I) provides materials suitable for providing organic LEDs which ensure good efficiencies, good operative lifetimes and a high stability to thermal stress, and a low use and operating voltage of the organic LEDs. The crosslinked or polymeric materials have excellent solubility in organic solvents, excellent film-forming properties, relatively high glass transition temperatures, high charge carrier mobilities, high stabilities of color emission, long operating times and improved thermal and mechanical stability and is relatively defect free.    DETAILED DESCRIPTION - Use of nitrogen-bonded five membered heterocyclic ring substituted dibenzofurans and dibenzothiophenes compounds (I) in monomeric, polymerized or crosslinked form, as host, blocker and/or charge transport materials is claimed.    X = S or O;    R1, R2 = (hetero)aryl, (cyclo)alkyl, heterocycloalkyl, crosslinkable or polymerizable group bonded via spacer, -NR3R4, -P(O)R5R6, -PR7R8, -S(O)2R9, -S(O)R10, -SR11 or -OR12 or C1 group; either    R3-R12 = (hetero)aryl, (cyclo)alkyl, heterocycloalkyl, crosslinkable or polymerizable group bonded via spacer; or    NR3R4 = cyclic radical which has 3-10 ring atoms and optionally substituted by one or more substituents comprising (cyclo)alkyl, heterocycloalkyl, (hetero)aryl or group with donor or acceptor action and/or may be fused to one or more further cyclic radicals having 3-10 ring atoms, where the fused radicals is optionally substituted by one or more substituents comprising (cyclo)alkyl, heterocycloalkyl, (hetero)aryl, crosslinkable or polymerizable group bonded via spacer, or a group with donor or acceptor action;    C1 = 5-membered heterocyclic (optionally saturated) radical of formula (a);    A1 = CRa1, N or NRb1;    A2 = CRc1, N or NRd1;    A3 = CRe1, N or NRf1;    A4 = CRg1, N or NRh1; either    Ra1-Rh1 = H, (hetero)aryl, (cyclo)alkyl, heterocycloalkyl, or crosslinkable or polymerizable group bonded via a spacer; or    (Ra1 or Rb1 and Rc1 or Rd1 and C or N), (Re1 or Rf1 and R91 or Rh1 and C or N), (Rc1 or Rd1 and Re1 or Rf1 and C or N) together = cyclic radical which has 3-10 ring atoms and optionally substituted by one or more substituents comprising (cyclo)alkyl, heterocycloalkyl, (hetero)aryl, crosslinkable or polymerizable group bonded via spacer, or group with donor or acceptor action, or may be fused to one or more further cyclic radicals having 3-10 ring atoms, where the fused radicals are optionally substituted by one or more substituents comprising (cyclo)alkyl, heterocycloalkyl, (hetero)aryl, crosslinkable or polymerizable group bonded via spacer, or group with donor or acceptor action;    n = 0-4;    m = 0-3; and    p = 1 or 2, where m+p is /~4.    Where C1 is bonded in the 2 or 4 position, or two units of (I) are bridged to one another via bond, linear or branched, optionally saturated bridge optionally interrupted by at least one heteroatom or via O, where (I) is bonded in place of Ra1-Rh1 or via and/or in place of R1 or R2. INDEPENDENT CLAIMS are included for:    (1) a carbazolyl substituted dibenzofurans and dibenzothiophenes compounds of formula (III);    (2) the preparation of (III);    (3) a crosslinked or polymerized material which comprises units of (III) or the compound (I); and    (4) an organic LED comprising (I) or (III).    R13, R14 = (hetero)aryl, (cyclo)alkyl, 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.