TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Cell: The solar cell comprises photoactive donor-acceptor junctions in the form of a bulk heterojunction. The solar cell is in the form of a single cell or in the form of a tandem cell or in the form of a multijunction cell (preferably in the form of a tandem cell, in which one subcell comprises (I) and at least one fullerene or fullerene derivative). The tandem cell additionally comprises at least one subcell whose absorption maximum in the relatively short-wave spectral region is 400-650 nm. In the solar cell, the photoactive region comprises at least one terrylene compound (I) in combination with at least one further different semiconductor material. The photoactive region comprises, as a further semiconductor material, at least one fullerene and/or fullerene derivative (preferably 60C or (6,6)-phenyl-61C-butyric acid methyl ester).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Preparation of terrylene compound (I) involves reacting boron compound of formula (II) in a coupling reaction with substituted naphthalene compound of formula (IIIa) or (IIIb) to obtain fused binaphthalenyl compound of formula (IV); ii) subjecting the reaction product obtained in step (i) to a cyclodehydrogenation to obtain at least one fused perylene compound of formula (V), iii) reacting (V) in a coupling reaction with substituted 9H-fluorene compound of formula (VI) to obtain at least one 9H-fluorene substituted fused perylene compound of formula (VII); and iv) subjecting the reaction product (VII) obtained in step (iii) to a cyclodehydrogenation to obtain at least one compound of formula (I). Preparation of terrylene compound (Ia) involves reacting fused perylene compound of formula (VIII) in a coupling reaction with substituted 9H-fluorene compound of formula (IX) to obtain 9H-fluorene substituted fused perylene compound of formula (X), and subjecting (X) to a cyclodehydrogenation to obtain at least one terrylene compound (Ia). Preparation of terrylene compound (Ib) involves reacting substituted boron compound of formula (XI) in a coupling reaction with a 9H-fluorene compound of formula (XII) to obtain 9H-fluorene substituted fused perylene compound of formula (XIII), subjecting (XIII) to a hydrolysis to obtain at least one anhydride compound of formula (XIV), subjecting the anhydride to a cyclodehydrogenation to obtain at least one terrylene compound of formula (XV), and subjecting (XV) to an imidation with an amine of formula (XVIa) or (XVIb) to give (Ib).R1a and R1b=H, 1-30C alkyl, 5-8C cycloalkyl, 6-14C (hetero)aryl;orR1a+R1b=2-4C alkylene (optionally substituted by 1-8 substituents selected from 1-4C alkyl, 5-8C cycloalkyl, 6-14C (hetero)aryl;A1=cyclic compound of formula (XVIc) or (XVId);LG=tosylate, Cl, Br or I;V1 and W1=Cl, Br, I or B(OR1a)(OR1b);R23b=phenyl (optionally substituted by 1 or 2 1-20C alkyl);Hal=Cl, Br or I.One of V1 and W1 radicals is Cl, Br or I, and the other V1 or W1 radical is a B(OR1a)(OR1b). Preferred Definitions:    R1 and R4=phenyl, thiophen-2-yl or 5-methylthiophen-2-yl;    R2 and R3=H or phenyl;or    R2+R3=-CH=CH-CH=CH-, naphthalene-1,8-diyl or biphenyl-2,2'-diyl;    R23=H, 1-20C alkyl, 6-14C aryl-1-20C alkyl, 6-14C aryl or 1-20C alkyl-6-14C aryl;    R27-R29=1-20C alkyl or phenyl (phenyl optionally substituted by mono to tri 1-20C alkyl).    SPECIFIC COMPOUNDS - 56 Compounds are disclosed as (I) e.g. compounds of formulae (IA)-(ID) and (IF).    EXAMPLE - A mixture of argon-saturated chlorobenzene (150 ml), 9H-fluorene substituted fused perylene compound of formula (IG) (3 g) (crude product, approximately 50%) and aluminum trichloride (suspended in 50 ml of chlorobenzene) (6.5 g) was stirred at 110 degrees C for 2.5 hours. The reaction mixture was mixed with dichloromethane and extracted with water. The organic phase was concentrated under reduced pressure. After work-up, (IA) (100 mg) was obtained as blue solid.