A rylene-based polychromophore of the general formula I in which the variables are each defined as follows: rylene is a radical of the formula which has been functionalized by at least one imide group, ester group or amide group and which may additionally be substituted by aryloxy, arylthio, hetaryloxy and/or hetarylthio; X is a rylenedicarboximide radical which absorbs at a different wavelength from the rylene radical, is bonded to the X radical in the peri-position via Y via a moiety —Y′-A-Y—, is bonded to the rylene radical and may likewise be substituted by aryloxy, arylthio, hetaryloxy and/or hetarylthio; A is a bridging member having at least one aromatic or heteroaromatic radical, the Y or Y and Y′ groups being bonded to the aromatic or heteroaromatic radical; Y is a moiety Y′ is a moiety where the moieties (i) and (ii) may be part of the ester groups of the rylene radical and the moieties (iii) are part of the imide groups of the rylene radical and the moieties (iv) are part of the amide groups of the rylene radical; R1 is hydrogen or C1-C18-alkyl, where the R1 radicals may be the same or different when they occur repeatedly; n is 1, 2 or 3; x is from 1 to 7.