NOVELTY - Fused (hetero)aryl compounds (I), are new.    USE - (I) or the oligomers, polymers or dendrimers are useful in electronic devices, preferably in organic electroluminescent devices, where the electronic devices are integrated organic electroluminescent devices, 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, organic laser diodes and organic plasmon emitting devices. (I) or the oligomers, polymers or dendrimers are useful: as hole transport material, matrix material, emitter material, electron-blocking material, hole injection material, hole blocking material and/or as electron transport material; as a matrix material in combination with one or more other matrix materials in an emitting layer; and as hole transport material in a hole transport layer or hole injection layer and/or as matrix material, preferably in combination with one or more other matrix materials in an emitting layer (all claimed).    ADVANTAGE - (I) provide organic electroluminescent device with improved durability, efficiency and operating voltage.    DETAILED DESCRIPTION - Fused (hetero)aryl compounds of formula (I), are new.    Y1, T = single bond, BR2, C(R2)2, R2C=CR2, Si(R2)2, C=O, C=NR2, O, S, SO, SO2, PR2, POR2 or NR2, where at least one Y1 is single bond;    Ph1 = phenyl group (optionally substituted with one or more R1);    Ar1 = 6-30 membered aromatic ring system (optionally substituted with one or more R1); either    R1, R2 = N(R3)2, C(=O)R3, P(=O)(R3)2, S(=O)R3, S(=O)2R3, CR3=C(R3)2, CN, NO2, Si(R3)3, B(OR3)2, OSO2R3, linear 1-40C-(thio)alkyl or -alkoxy, branched or cyclic 3-40C-(thio)alkyl or -alkoxy, 2-40C-alkenyl or 2-40C-alkynyl (all optionally substituted with one or more R3, and where one or more nonadjacent CH2- groups are optionally replaced by R3C=CR3, CC, Si(R3)2, Ge(R3)2, Sn(R3)2, C=O, C=S, C=Se, C=NR3, P(=O)(R3), SO, SO2, NR3, O, S or CONR3, and one or more H atoms are optionally replaced by D, F, Cl, Br, I, CN or NO2), H, D, F, Cl, Br, I, CHO, OH or 5-60 membered mono- or polycyclic (hetero)aromatic ring system or 5-60 membered (hetero)aryloxy (both optionally substituted by non-aromatic residue of R3); or    two or more R1 and/or R2 bonded together = mono- or polycyclic, aliphatic or aromatic ring system; either    R3 = H, D, F or 1-20C-aliphatic and/or (hetero)aromatic organic residue, in which one or more H atoms are optionally replaced by D or F; or    two or more R3 = mono- or polycyclic, aliphatic or aromatic ring system; and    m = 0 or 1, and when n = 0, a group R1 is bound instead of a group Y;    n = 0 or 1, and the upper sum of all values of n are 1 or 2, and when n = 0, a group R1 is bound instead of a group Y; and    p = 0 or 1    (I) exclude 3-(9H-carbazol-9-yl)-6-(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8-dimethyl-8H-indolo(3,2,1-de)acridine, 6-(4,6-diphenyl-1,3,5-triazin-2-yl)-3-(3,6-diphenyl-9H-carbazol-9-yl)-8,8-dimethyl-8H-indolo(3,2,1-de)acridine, 7-(9H-carbazol-9-yl)-10-(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8-dimethyl-8H-indolo(3,2,1-de)acridine, 10-(9H-carbazol-9-yl)-3-(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8-dimethyl-8H-indolo(3,2,1-de)acridine, 3,3'-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8,8',8'-tetramethyl-8H,8'H-6,6'-biindolo(3,2,1-de)acridine, 6,6'-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8,8',8'-tetramethyl-8H,8'H-3,3'-biindolo(3,2,1-de)acridine, 6-(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8-dimethyl-3-(2-phenyl-9H-carbazol-9-yl)-8H-indolo(3,2,1-de)acridine, 10,10'-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8,8',8'-tetramethyl-8H,8'H-6,6'-biindolo(3,2,1-de)acridine, 1,3-bis(3-(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8-dimethyl-8H-indolo(3,2,1-de)acridin-6-yl)benzene and 1,3-bis(10-(4,6-diphenyl-1,3,5-triazin-2-yl)-8,8-dimethyl-8H-indolo(3,2,1-de)acridin-6-yl)benzene, and no more than a group R1, which is a N(R3)2 with R3 as an aromatic residue bonded to a single triarylamine group in (I).    INDEPENDENT CLAIMS are included for:    (1) the preparation of (I);    (2) oligomers, polymers or dendrimers containing one or more (I), where one or more bonds of (I) remain(s) to the polymer, oligomer or dendrimer; and    (3) a formulation comprising (I) or their oligomers, polymers or dendrimers and at least a solvent.