3,4;9,10-Perylenetetracarboxylic diimide of the formula I wherein the compound of the formula comprises at least one group A wherein each group A is independently selected from a group of the following formula wherein * denotes the bonding site to the remainder of the molecule; R 1 and R 2, independently of each other, are selected from hydrogen, C 1 -C 30 -alkyl, C 2 -C 30 -alkenyl, C 2 -C 30 -alkynyl, C 3 -C 12 -cycloalkyl and C 6 -C 24 -aryl wherein the two last-mentioned radicals are unsubstituted or carry one, two or three radicals selected from C 1 -C 10 -alkyl; x is 0 or 1; y is 0 or 1; Ar1 is C 6 -C 24 -aryl which does not bear a substituent R Ar1 or bears 1, 2 or 3 identical or different substituent(s) R Ar1, where each R Ar1, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkylsulfanyl, C 2 -C 30 -alkenyl and C 2 -C 30 -alkynyl; Ar2 is C 6 -C 24 -aryl which does not bear a substituent R Ar2 or bears 1, 2 or 3 identical or different substituent(s) R Ar2, where each R Ar2, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkylsulfanyl, C 2 -C 30 -alkenyl and C 2 -C 30 -alkynyl; R 3, R 4, R 5 and R 6, independently of each other, are selected from hydrogen and a group of formula z -Ar3-X-#, wherein # denotes the bonding site to the remainder of the molecule; z is 0 or 1; X is O or S; Ar3 C 6 -C 24 -aryl which does not bear a substituent R Ar3 or bears 1, 2 or 3 identical or different substituent(s) R Ar3, wherein each R Ar3, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkyl-sulfanyl, C 2 -C 30 -alkenyl, C 3 -C 12 -cycloalkynyl, C3-C12-cycloalku=yL and C 6 -c 24 -aryl. each group A is independently selected from a group of the following formula wherein * denotes the bonding site to the remainder of the molecule; R 1 and R 2, independently of each other, are selected from hydrogen, C 1 -C 30 -alkyl, C 2 -C 30 -alkenyl, C 2 -C 30 -alkynyl, C 3 -C 12 -cycloalkyl and C 6 -C 24 -aryl wherein the two last-mentioned radicals are unsubstituted or carry one, two or three radicals selected from C 1 -C 10 -alkyl; * denotes the bonding site to the remainder of the molecule; R 1 and R 2, independently of each other, are selected from hydrogen, C 1 -C 30 -alkyl, C 2 -C 30 -alkenyl, C 2 -C 30 -alkynyl, C 3 -C 12 -cycloalkyl and C 6 -C 24 -aryl wherein the two last-mentioned radicals are unsubstituted or carry one, two or three radicals selected from C 1 -C 10 -alkyl; x is 0 or 1; y is 0 or 1; Ar1 is C 6 -C 24 -aryl which does not bear a substituent R Ar1 or bears 1, 2 or 3 identical or different substituent(s) R Ar1, where each R Ar1, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkylsulfanyl, C 2 -C 30 -alkenyl and C 2 -C 30 -alkynyl; Ar2 is C 6 -C 24 -aryl which does not bear a substituent R Ar2 or bears 1, 2 or 3 identical or different substituent(s) R Ar2, where each R Ar2, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkylsulfanyl, C 2 -C 30 -alkenyl and C 2 -C 30 -alkynyl; R 3, R 4, R 5 and R 6, independently of each other, are selected from hydrogen and a group of formula z -Ar3-X-#, wherein # denotes the bonding site to the remainder of the molecule; z is 0 or 1; X is O or S; Ar3 C 6 -C 24 -aryl which does not bear a substituent R Ar3 or bears 1, 2 or 3 identical or different substituent(s) R Ar3, wherein each R Ar3, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkyl-sulfanyl, C 2 -C 30 -alkenyl, C 3 -C 12 -cycloalkynyl, C3-C12-cycloalku=yL and C 6 -c 24 -aryl. # denotes the bonding site to the remainder of the molecule; z is 0 or 1; X is O or S; Ar3 C 6 -C 24 -aryl which does not bear a substituent R Ar3 or bears 1, 2 or 3 identical or different substituent(s) R Ar3, wherein each R Ar3, independently of each other, is selected from C 1 -C 30 -alkyl, C 1 -C 30 -haloalkyl, C 1 -C 30 -alkoxy, C 1 -C 30 -alkyl-sulfanyl, C 2 -C 30 -alkenyl, C 3 -C 12 -cycloalkynyl, C3-C12-cycloalku=yL and C 6 -c 24 -aryl.