TECHNOLOGY FOCUS - ELECTRONICS - Preferred Device: The electronic device is an electroluminescent device comprising a cathode, an anode, and between them a light emitting layer containing a host material and a phosphorescent light-emitting material, where the host material is the compound (I) or (III). The device comprises a cathode, an anode, and an electron transport material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): Preparation of the compounds (VIa) and (VIb) involves oxidizing azapyrene (II) with sodium perchlorate or sodium periodate in presence of ruthenium trichlorate in methylenechloride to give (VIa) or (VIb). Preferred Compound: The compound is selected from 7 compounds, e.g. a compound of formulae (IIa) or (IVa).X1=N, or CH;Y'=O or NR25;R25=6-18C aryl (optionally substituted by 1-18C alkyl or 1-18C alkoxy), or 1-18C alkyl (optionally interrupted by -O-);R5-R8=H;R1-R3=H, 1-18C alkyl (optionally substituted by E' and/or interrupted by D'), 6-24C aryl (optionally substituted by G'), 2-20C heteroaryl (optionally substituted by G' selected from a group of 27 compounds e.g. group of formula (i), (ii), 1-18C alkoxy (optionally substituted by E' and/or interrupted by D'), a group of formula (I'), or -L1-NR'25R26;u and v=0 or 1;R211, R'211, R212 and R'212=H, 1-18C alkyl or 1-18C alkoxy;R213 and R214=H or 1-18C alkyl;Ar1=-NR25R'26, 6-24C aryl (optionally substituted by G'), 2-20C heteroaryl (optionally substituted by G');L1=single bond, or a bridging unit BU, such as (iii), (iv), or (v);D'=-O- or -NR25-;E'=-OR29, -NR25R26, -CN, or F;G'=E', 1-18C alkyl, (optionally interrupted by D'), 1-18C perfluoroalkyl, 1-18C alkoxy, (optionally substituted by E' and/or interrupted by D');R'25 and R'26=phenyl, naphthyl, anthryl, biphenylyl, 2-fluorenyl, phenanthryl, or perylenyl (all optionally substituted by a group of 10 compounds e.g. a group of formula (vi));N(R'25+R'26)=heteroaromatic ring, or ring system of formula (vii);m'=0-2;m=0 or 1;R41=Cl, F, CN, N(R45)2, a 1-25C alkyl, 4-18C cycloalkyl, 1-25C alkoxy (in which at least one carbon atoms which are not in neighbourhood to each other is replaced by -NR45-, -O-, -S-, or -C(=O)-O-, and/or where at least one H is replaced by F), 6-24C aryl, or 6-24C aryloxy, (where at least one carbon atoms is replaced by O, S, or N, and/or is optionally substituted by at least one non-aromatic groups R41, or at least two R41 to form a ring system);R45=1-25C alkyl, 4-18C cycloalkyl, (in which at least one carbon atoms which are not in neighbourhood to each other is replaced by -NR''45-, -O-, -S-, -C(=O)-O-, or, -O-C(=O)-O-, and/or where at least one H is replaced by F), 6-24C aryl, or 6-24C aryloxy (where at least one carbon atoms is replaced by O, S, or N, and/or is optionally substituted by at least one non-aromatic groups R41);R''45=1-25C alkyl, or 4-18C cycloalkyl;R216 and R217=H, halo, -CN, 1-18C alkyl (optionally substituted by E' and/or interrupted by D'), 6-24C aryl (optionally substituted by G'), 2-20C heteroaryl (optionally substituted by G'), 2-18C alkenyl, 2-18C alkynyl, 1-18C alkoxy (optionally substituted by E' and/or interrupted by D'), 7-25C aralkyl, -C(=O)-R127, -C(=O)OR127, or -C(=O)NR127R126;R126 and R127=6-18C aryl (optionally substituted by 1-18C alkyl (optionally interrupted by -O-), or 1-18C alkoxy. Preferred Definitions:    X1=N or CH;    R1=H.    SPECIFIC COMPOUNDS - 98 Compounds are specified as the compound (I) or (III), e.g. 2,6,8-triphenyl-1,3,7-triaza-pyrene; 2,6,8-tri-naphthalen-2-yl-1,3,7-triaza-pyrene; 2,6,8-triphenyl-benzo(gh)perimidine; 2,6,8,9,10-pentaphenyl-9H-1,3,9,11-tetraaza-cyclopenta(e)pyrene; and 2,6,8-triphenyl-1,3,9,12-tetraaza-benzo(e)pyrene-10,11-dicarbonitrile (Ia).