NOVELTY - Aromatic compounds (I) are new.    USE - (I) are useful: for the preparation of dimer, trimer, tetramer, pentamer, oligomer, polymer or dendrimer, mixture and solution; in an electronic device, preferably organic electroluminescent devices (organic light emitting diode, polymer light emitting diode), organic field-effect transistors, organic thin-film transistor, organic light-emitting transistor, organic integrated circuits, organic solar cell, organic field-quench devices, light emitting electrochemical cell, organic laser diodes, or organic photoreceptors. (I) are useful as matrix material for fluorescence or phosphorescence compounds, hole transport material, hole injection material, electron block material, exciton block material, electron transport material, or hole block material, when at least one substituent of R1 and/or R2 is heteroaryl group, which represents an electron arm heterocycle, or for C(=O)Ar4, P(=O)Ar2, S(=O)Ar4 or S(O)2Ar4 or when X is B, P=O, P=S or 1,3,5-triazine (all claimed).    ADVANTAGE - (I) provide organic electroluminescent devices with improved efficiency and lifetime. (I) exhibit high thermal stability.    DETAILED DESCRIPTION - Aromatic compounds of formula (I) are new.    X = N, B, P, P=O, P=S, 1,3,5-triazine, or N(Ar2)3;    Ar1 = a group that stretches together with C-C to form an aryl- or heteroaryl group with 5-40 aromatic ring atoms and optionally substituted by at least one R1;    Ar2 = a bivalent or heteroaryl group with 5-30 aromatic ring atoms, which are optionally substituted with at least one R1, where 2Ar2 are bonded to X through a single bond or a bridge, preferably 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;    Ar3 = a monovalent or heteroaryl group with 5-16 aromatic ring atoms, which are optionally substituted by at least one R1, where 2Ar3 are bonded to X through a single bond or a bridge, preferably 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    R1 = H, D, F, Cl, Br, I, CHO, C(=O)Ar4, P(=O)(Ar4)2, S(=O)Ar4, S(=O)2Ar4, CR2=CR2Ar4, CN, NO2, Si(R2)3, B(OR2)2, B(R2)2, B(N(R2)2)2, OSO2R2, 1-40C-alkyl, 1-40C-alkoxy or 1-40C-thioalkoxy group or cyclic 3-40C-alkyl, 3-40C-alkoxy or 3-40C-thioalkoxy atoms (optionally substituted by one or more R2, and where at least one non-adjacent CH2 group are optionally substituted 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, and at least one H atoms are optionally substituted by F, Cl, Br, I, CN or NO2), aryl or heteroaryl with 5-60 aromatic ring (optionally substituted by at least one R2), or an aryloxy- or heteroaryloxy group (optionally substituted by at least one R2); or    two or more adjacent R1 = a mono- or polycyclic, aliphatic or aromatic ring system;    Ar4 = aryl or heteroaryl with 5-30 aromatic ring atoms that are optionally substituted by at least one non-aromatic R1; either    R2 = H, D or 1-20C-aliphatic, 1-20C-aromatic and/or 1-20C-heteroaromatic hydrocarbon, in which H atoms are optionally substituted by F; or    two or more adjacent R2 = a mono- or polycyclic, aliphatic or aromatic ring system;    n = 2 or 3;    p = 0-2;    q = 1 (when p is 0) or 1 or 2 (when p is 1); and    r = 0-2.    INDEPENDENT CLAIMS are included for:    (1) a dimer, trimer, tetramer, pentamer, oligomer, polymer or dendrimer comprising (I);    (2) a mixture comprising (I) and at least a further compound;    (3) a solution comprising (I) or the mixture and at least an organic solvent; and    (4) the preparation of (I).