TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The device further comprises at least one electron donor or electron acceptor. The device further comprises a pair of electrodes, and at least one layer of semiconducting material between the electrodes, where at least one of the layers comprises (I). At least two layers of semiconducting materials are provided between the electrodes, where the layers form a heterojunction and at least one of the layers comprises a photosensitive semiconducting material which comprises (I). At least two layers include (I). The layer or at least one of the layers of semiconducting material includes a mixture or blend of (I) and another organic semiconducting material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: (I) is substituted with at least two alkynyl groups, where at least two of the alkynyl groups are located in nonadjacent substitution positions. At least one polycyclic aromatic substructure has at least five or six aromatic rings. (I) is photosensitive. (I) comprises additional substituents comprising alkyl, cycloalkyl, cycloalkylalkyl, alkoxy, cycloalkoxy, cycloalkylalkoxy, alkenyl, aryl, aryloxy, arylalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, heteroarylalkyl, alkoxyalkyl, cycloalkoxyalkyl, aryloxyalkyl, haloalkyl, trialkylsilyl dialkylarylsilyl, alkyldiarylsilyl or triarylsilyl (all optionally substituted), halogen or nitrile. The substructure comprises an alternant polycyclic benzenoid aromatic ring system. The alternant polycyclic benzenoid ring system comprises a substructure template comprising at least one benzo(def)chrysene, perylene or dibenzo(a,h)anthracene. The alternant polycyclic benzenoid ring system is at least one dibenzo(def,mno)chrysene, dibenzo(b,def)chrysene, dibenzo(a,j)perylene, pyranthrene, benzo(rst)phenanthro(10,1,2-cde)pentaphene, anthra(9,1,2-cde)benzo(rst)pentaphene, ovalene or hexabenzo(bc,ef,hi,kl,no,qr)coronene. The substructure comprises rings in addition to or alternative to benzenoid rings. The substructure has rubicene structure. The polycyclic compound contains at least two alkynyl substituents of formula (-CC-X(R)n) (II). If the alkynyl group (II) is located at the peripheral C-atom of rubicene, then X is not a C-atom. The device includes fullerene or a fullerene derivative. (I) does not undergo chemical reaction, in particular a C-C bond forming reaction, with another component of the device. (I) does not undergo a chemical reaction including a cycloaddition reaction, with fullerene or the fullerene derivative. The mixture or blend includes an electron accepting fullerene derivative and (I) is an electron donating compound which does not undergo a chemical reaction with the fullerene derivative. Another layer of the device is an electron accepting fullerene derivative and (I) is an electron donating compound which does not undergo a chemical reaction with the fullerene derivative.X = atom comprising groups IIIa-Vlb elements;R = alkyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, heteroarylalkyl, alkoxyalkyl, cycloalkoxyalkyl, aryloxyalkyl, haloalkyl, trialkylsilyl, dialkylarylsilyl, alkyldiarylsilyl or triarylsilyl (all optionally substituted) or H;n = 1-(v-1); andv = valency of X. Preferred Definitions:    X = C or Si; and    n = 3.    SPECIFIC COMPOUNDS - The use of 17 compounds (I) is specifically claimed e.g. 7,14-bis((triisopropylsilyl)ethynyl)dibenzo(c,pqr)tetraphene of formula (Ia), 7,14-bis((triethylsilyl)ethynyl)dibenzo(c,pqr)tetraphene, 7,14-bis((trimethylsilyl)ethynyl)dibenzo(c,pqr)tetraphene, 7,14-di(oct-1-ynyl)-4b(1),4b(2)-dihydrodibenzo(c,pqr)tetraphene and 7,14-di(dodec-1-ynyl)-4b(1),4b(2)-dihydrodibenzo(c,pqr)tetraphene.