Rylene dyes of the general formula I ##STR00001## where the variables are defined as follows: R is hydrogen; optionally substituted C.sub.1-C.sub.30-alkyl, C.sub.5-C.sub.8-cycloalkyl, aryl or hetaryl; R' is bromine; cyano; --NR.sup.3.sub.2; optionally substituted aryloxy, arylthio, hetaryloxy or hetarylthio; optionally substituted C.sub.3-C.sub.18-alk-1-ynyl; X, Y are both hydrogen or together are a radical of the formula Ia ##STR00002## n is 2, 3, 4 or additionally 1 when X and Y are a radical of the formula Ia; n' is from 1 to 4; m is from 0 to 6.