TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) comprises: either reaction of a rylene dianhydride compound of formula (Ib) with an amine compound of formula (NH2-X1(Ri)x) and optionally with an amine compound of formula (NH2-X2(Rii)y) to give (I) (where n is 1 or 2); or reaction of 6-bromo-benzo(de)isoquinoline-1,3-dione compound of formula (IIIa) with a diborane compound of formula ((RrO)2-B-B-(RrO)2) to give an isoquinoline compound of formula (V), reaction of (V) with 6-bromo-benzo(de)isoquinoline-1,3-dione compound of formula (IIIb) in the presence of a transition metal catalyst and a base of a Suzuki-coupling reaction to give a benzo(de)isoquinoline-1,3-dione compound of formula (VI), and cyclodehydration of (VI) in the presence of an organic reaction medium having hydroxy- and amino functional and preferably containing an undissolved base to give (I) (where n is 2-4); or reaction of a perylene-3,4-dicarboxylic acid imide of formula (VII) with an isoquinoline-1,3-dione compound of formula (VIII) in the presence of a base stabilized solvent and an alkali- or alkaline earth metal-containing base to give (I) (where n is 3 or 4).o, p = 1 or 2;Rr = H, 1-30C alkyl, 5-8C cycloalkyl, aryl, hetaryl or a five membered ring (containing O and B atoms and the carbon atom is replaced by up to 4 of 1-30C alkyl-, 5-8C cycloalkyl-, aryl or hetaryl);Z = H, Br or Cl; andq = 0 or 1. Preferred Definitions:    X1(Ri)x, X2(Rii)y = a-(A)p1-C(Ri)x, a substituted phenyl compound of formula (II.2), (II.3) or (II.4), a substituted pyridine compound of formula (II.5), (II.6) or (II.7), a substituted pyrimidine compound of formula (II.8), (II.9) or (II.10) or triazine compound of formula (II.11), (II.12) or (II.13);    a = a bond to the imide nitrogen atom;    x = 2 (in (II.11), (II.12) or (11.13)), or 2 or 3 (in (II.14));    A = 1-10C alkylene (interrupted by -O- or -S-);    Rn1-Rn4 = H;    x, y = 2 or 3; and    p1 = 0 or 1.    SPECIFIC COMPOUNDS - 4 Compounds (I) are specifically disclosed i.e. bis(piperidine-2,6-dione) compound of formulae (Ia), (Ic) and (Id), and 2,9-bis-(1-heptyl-octyl)-anthra(2,1,9-def;6,5,10-d'e'f')diisoquinoline-1,3,8,10-tetraone.    EXAMPLE - N-(1-Heptyloctyl)-9-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-perylen-3,4-dicarboxylic acid imide (0.2 g) and N-(1-heptyloctyl)-9-bromoperylene-3,4-dicarbonic acid imide (0.37 g) were dissolved in toluene (15 ml). To the above mixture, sodium bicarbonate in water (10 ml) and ethanol (5 ml) were added, followed by the addition of a palladium compound of formula ((Pd(PPh3)4)) (16 mg). The reaction mixture was stirred for 16 hours at 80 degrees C. The reaction mixture was worked up to give N,N'-bis(1-heptyloctyl)-9,9'-biperylen-3,4:3',4'-bis(dicarbonic acid imide) (A). (A) (0.2 g), potassium carbonate (1.26 g) and ethanol amine (1.7 g) were stirred for 3 hours at 160 degrees C under argon atmosphere. After cooling the mixture, methanol (10 ml) was added. The reaction mixture was worked up to give N,N'-di(1-heptyloctyl)quaterrylene-3,4:13,14-tetracarbonic acid diimide (0.165 g).