NOVELTY - Substituted heterocyclic compounds (I) are new.    USE - (I) or the oligomer, polymer or the dendrimer is useful as a hole transport material in a hole transport- or hole injection layer, as a matrix material in an emitting layer, as an electron blocking material or as an exciton-blocking material of electronic devices, preferably organic electroluminescent devices (preferred), organic integrated circuits, organic field-effect transistors, organic thin film transistors, organic light-emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells and organic laser diodes (all claimed).    ADVANTAGE - (I) exhibits: low sublimation temperature, high thermal stability and high oxidation stability in solution; and high hole mobility. The electronic device comprising (I), exhibits good efficiency and long service life, and requires low operating voltage.    DETAILED DESCRIPTION - Substituted heterocyclic compounds of formula (I) are new.    Ar1 = aromatic ring with 6-24 aromatic ring atoms or electron-rich heteroaryl with 5-18 aromatic ring atoms (both optionally substituted by at least one group R2);    L = 1-20C alkylene, 2-20C alkenylene, 2-20C alkynylene (in all groups at least one CH2 group may be replaced by C=O, C=NR2, C=O-O, C=O-NR2, Si(R2)2, NR2, P(=O)(R2), O, S, SO or SO2 and in all groups at least one H may be replaced by D, F, Cl, Br, I, CN or NO2), aromatic ring with 6-24 aromatic ring atoms (optionally substituted by at least one group R2), single bond, C=O, C=NR2, Si(R2)2, PR2, P(=O)(R2), O, S, SO, and/or SO2;    X = C(R1)2, Si(R1)2, NR1, PR1, O or S;    Z = CR2 or N; either    R1 = 1-20C alkyl, 1-20C alkoxy, 1-20C thioalkyl (all linear) or 3-20C alkyl, 3-20C alkoxy, 3-20C thioalkyl (all branched or cyclic), 2-20C alkenyl, 2-20C alkynyl (in all groups at least one CH2 group may be replaced by -R3C=CR3-, -CC-, Si(R3)2, C=O, C=S, C=NR3, -C(=O)O-, -C(=O)NR3, NR3, P(=O)(R3), -O-, -S-, SO or SO2, and in all groups at least one H may be replaced by D, F, Cl, Br, I, CN or NO2), aromatic ring with 6-30 aromatic ring atoms (all optionally substituted by at least one group R3), H, D, F, Cl, Br, I, C(=O)R3, CN, Si(R3)3, NO2, P(=O)(R3)2, S(=O)R3 or S(=O)2R3; or    at least 2 non-aromatic R1 = ring; either    R2 = 1-20C alkyl, 1-20C alkoxy, 1-20C thioalkyl (all linear) or 3-20C alkyl, 3-20C alkoxy, 3-20C thioalkyl (all branched or cyclic), 2-20C alkenyl, 2-20C alkynyl (in all groups at least one CH2 group may be replaced by -R3C=CR3-, -CC-, Si(R3)2, C=O, C=S, C=NR3, -C(=O)O-, -C(=O)NR3, NR3, P(=O)(R3), -O-, -S-, SO or SO2, and in all groups at least one H may be replaced by D, F, Cl, Br, I, CN or NO2), (hetero)aromatic ring with 5-30 aromatic ring atoms, (hetero)aryloxy with 5-30 aromatic ring atoms (all optionally substituted by at least one group R3), H, D, F, Cl, Br, I, C(=O)R3, CN, Si(R3)3, NO2, P(=O)(R3)2, S(=O)R3 or S(=O)2R3; or    at least 2R2 = ring; either    R3 = 1-20C alkyl, 1-20C alkoxy, 1-20C thioalkyl (all linear) or 3-20C alkyl, 3-20C alkoxy, 3-20C thioalkyl (all branched or cyclic), 2-20C alkenyl, 2-20C alkynyl (in all groups at least one CH2 group may be replaced by -R4C=CR4-, -CC-, Si(R4)2, C=O, C=S, C=NR4, -C(=O)O-, -C(=O)NR4, NR4, P(=O)(R4), -O-, -S-, SO or SO2, and in all groups at least one H may be replaced by D, F, Cl, Br, I, CN or NO2), (hetero)aromatic ring with 5-30 aromatic ring atoms, (hetero)aryloxy with 5-30 aromatic ring atoms (all optionally substituted by at least one group R4), H, D, F, Cl, Br, I, C(=O)R4, CN, Si(R4)3, NO2, P(=O)(R4)2, S(=O)R4 or S(=O)2R4; or    at least 2R3 = ring; either    R4 = 1-20C aliphatic organic group, 1-20C (hetero)aromatic organic group (in both groups at least one H may be replaced by D or F), H, D or F; or    at least 2R4 = ring; and    n = 0 or 1, where at least two indices n = 1.    Provided that: Z does not carry substituents or Z represents C when Z carries a substituent; when n is zero the corresponding position is bonded by the group R2; (I) does not comprise carbazole; and (I) comprises at least one group Ar1, which is an electron-rich heteroaryl with 5-18 aromatic ring atoms or an aromatic ring with 12-24 aromatic ring atoms. INDEPENDENT CLAIMS are also included for:    (1) preparing (I);    (2) an oligomer, polymer or dendrimer comprising (I), where the bonds to the polymer, oligomer or the dendrimer are localized at any position in (I), which is substituted with R1 or R2; and    (3) a formulation comprising (I) or at least one oligomer, polymer or dendrimer, and at least one solvent.