Mixtures comprising compounds of formula wherein the arrows denote substitution at the aromatic ring without specifically indicating the relative position to the depicted keto-group if not mentioned otherwise hereinafter and wherein B is either missing and the two aromatic rings are then therefore substituted with hydrogen, or where n or m are not zero alternatively also with R 1 or R 2 respectively, at the position where B is depicted to be bound at the aromatic ring or is sulfur or oxygen, whereby B is preferably missing or sulfur and more preferably B is missing n is 0, 1 or 2, preferably 0 or 1 and more preferably 0 R 1 is independently of other substituents R 1 which may be present selected from the group consisting of C 1 -C 18 -alkyl, C 2 -C 18 -alkenyl, C 1 -C 18 -alkoxy, C 1 -C 18 -alkylthio C 6 -C 14 -aryl, C 6 -C 14 -aryloxy, C 6 -C 14 -arylthio, -N(R 5) 2, fluoro, chloro and COOR 5 with R 5 being hydrogen or C 1 -C 18 -alkyl m is 0, 1 or 2, preferably 0 or 1 and more preferably 0 R 2 is independently of other substituents R 2 which may be present selected from the group consisting of C 1 -C 18 -alkyl, C 2 -C 18 -alkenyl, C 1 -C 18 -alkoxy, C 1 -C 18 -alkylthio, C 6 -C 14 -aryl, C 6 -C 14 -aryloxy, C 6 -C 14 -arylthio, -N(R 5) 2, fluoro, chloro and COOR 5, with R 5 being hydrogen or C 1 -C 18 -alkyl and v is 0 or 1, preferably 0 and the substituents L-Het[[CHR 3 CHR 4 O] p -H] t if present and L-Het-[CHR 3 CHR 4 O] q -H] t independently of each other occupy the ortho-, meta or the para-position, more preferably the ortho- or the para-position and even more preferably the para-position at their respective aromatic ring and with respect to the keto-function depicted in formula and wherein L is independently missing or a methylene group, i.e. Het is either directly bound to the aromatic ring or via a methylene group Het is independently sulphur, oxygen, N(C 1 -C 18 -Alkyl), or N, preferably oxygen t is 1 for Het = sulphur, oxygen, N(C 1 -C 18 -Alkyl) and is 2 for for Het = N R 3 and R 4 are either identically hydrogen or one of R 3 and R 4 is hydrogen and the other is methyl, whereby, in a preferred embodiment R 3 and R 4 are identically hydrogen and and p and q independently of each other represent an integer of 0 or more, preferably 1 or more, preferably of from 1 to 20, more preferably of from 1 to 10 wherein with respect to the number of repeating units p and q, however, at least 50 wt.-%, preferably at least 55 wt.-% and even more preferably at least 60 wt.-% of the total weight of compounds of formula within the mixture are those of formula wherein • q, where v is 0 and t is 1 or • at least one of p and q, where both t are 1 or • at least one of all q, where v=0 and t is 2 or • at least one of all p and all q, where v=1 and where at least one t is 2 is 3 or more, preferably of 3 to 20, even more preferably 3 to 10 and yet even more preferably 3, 4, 5, 6, 7 or 8 wherein none of the single compounds of formula is present in an amount of more than 50 wt.-% with respect to the total weight of compounds of formula in the mixture. the arrows denote substitution at the aromatic ring without specifically indicating the relative position to the depicted keto-group if not mentioned otherwise hereinafter and wherein B is either missing and the two aromatic rings are then therefore substituted with hydrogen, or where n or m are not zero alternatively also with R 1 or R 2 respectively, at the position where B is depicted to be bound at the aromatic ring or is sulfur or oxygen, whereby B is preferably missing or sulfur and more preferably B is missing n is 0, 1 or 2, preferably 0 or 1 and more preferably 0 R 1 is independently of other substituents R 1 which may be present selected from the group consisting of C 1 -C 18 -alkyl, C 2 -C 18 -alkenyl, C 1 -C 18 -alkoxy, C 1 -C 18 -alkylthio C 6 -C 14 -aryl, C 6 -C 14 -aryloxy, C 6 -C 14 -arylthio, -N(R 5) 2, fluoro, chloro and COOR 5 with R 5 being hydrogen or C 1 -C 18 -alkyl m is 0, 1 or 2, preferably 0 or 1 and more preferably 0 R 2 is independently of other substituents R 2 which may be present selected from the group consisting of C 1 -C 18 -alkyl, C 2 -C 18 -alkenyl, C 1 -C 18 -alkoxy, C 1 -C 18 -alkylthio, C 6 -C 14 -aryl, C 6 -C 14 -aryloxy, C 6 -C 14 -arylthio, -N(R 5) 2, fluoro, chloro and COOR 5, with R 5 being hydrogen or C 1 -C 18 -alkyl and v is 0 or 1, preferably 0 and L is independently missing or a methylene group, i.e. Het is either directly bound to the aromatic ring or via a methylene group Het is independently sulphur, oxygen, N(C 1 -C 18 -Alkyl), or N, preferably oxygen t is 1 for Het = sulphur, oxygen, N(C 1 -C 18 -Alkyl) and is 2 for for Het = N R 3 and R 4 are either identically hydrogen or one of R 3 and R 4 is hydrogen and the other is methyl, whereby, in a preferred embodiment R 3 and R 4 are identically hydrogen and p and q independently of each other represent an integer of 0 or more, preferably 1 or more, preferably of from 1 to 20, more preferably of from 1 to 10 • q, where v is 0 and t is 1 or • at least one of p and q, where both t are 1 or • at least one of all q, where v=0 and t is 2 or • at least one of all p and all q, where v=1 and where at least one t is 2