Rylene derivatives of the general formula I in which the variables are each defined as follows: X are joined to one another with formation of a six-membered ring to give a radical of the formula (a), (b) or (c) are both a —COOM radical; are both hydrogen or one of the two radicals is hydrogen and the other radical is halogen or a radical of the formula (d) Y are joined to one another with formation of a six-membered ring to give a radical of the formula (a) when one of the two X radicals is hydrogen and the other X radical is halogen or a radical of the formula (d) or when both X radicals are hydrogen or together are a radical of the formula (a), (b) or (c); are joined to one another with formation of a six-membered ring to give a radical of the formula (b) when one of the two X radicals is hydrogen and the other X radical is halogen or a radical of the formula (d) or when both X radicals are hydrogen or a —COOM radical or together are a radical of the formula (c); are joined to one another with formation of a six-membered ring to give a radical of the formula (c) when one of the two X radicals is hydrogen and the other X radical is halogen or a radical of the formula (d) or when both X radicals are hydrogen or a —COOM radical or together are a radical of the formula (c) which may be arranged in the cis or trans position to the other (c) radical; are both a —COOM radical when one of the two X radicals is hydrogen and the other X radical is halogen or a radical of the formula (d) or when both X radicals are hydrogen or a —COOM radical, M being different from hydrogen in the case that one X radical is a radical of the formula (d); are both hydrogen or one of the two radicals is hydrogen and the other radical is halogen or a radical of the formula (d) when both X radicals are hydrogen or one of the two X radicals is hydrogen and the other X radical is halogen or a radical of the formula (d); R are identical or different radicals: substituted or unsubstituted aryloxy, arylthio, hetaryloxy or hetarylthio; R′ is hydrogen; substituted or unsubstituted alkyl, cycloalkyl, aryl or hetaryl; A are each independently substituted or unsubstituted phenylene, naphthylene or pyridylene; M is hydrogen, ammonium or alkali metal cation; R″ are each independently hydrogen, alkyl, cycloalkyl, aryl or hetaryl, or are joined together with formation of a 5- to 7-membered, fused or unfused and substituted or unsubstituted ring comprising the two oxygen atoms and also the boron atom; R1 is hydrogen or alkyl, where the R1 radicals may be the same or different when they occur more than once; R2,R3 are each independently hydrogen; substituted or unsubstituted alkyl, aryl or hetaryl; m is 1 or 2; n is from 3 to 6 where m=1; is from 2 to 8 where m=2, and mixtures thereof.