A compound of the formula la wherein each L, each L 1, each L 2, each L 3, each L 4, each L 5, each L 6, each L 7 and each L 8 is identical and L, L 1, L 2, L 3, L 4, L 5, L 6, L 7 and L 8 independently of one another are hydrogen, R 1, OR 1, SR 1, NR 1 R 2, halogen, NO 2, CN, NR 1 COR 2, COOR 1, OCOR 1, CONR 1 R 2, OCOOR 1, OCONR 1 R 2, NR 1 COOR 2, SO 3 H, SO 3 M, SOR 1, SO 2 R 1 or are COT; and/ or the pairs L 3 and L 5 together are a single bond, CR a R b, CO, O, S, NR c or NCOR c; provided that L 3 and L 5 together are no single bond, when the respective X denotes a single bond; and/or the pairs L 1 and L 3, L 1 and L, L 5 and L 7 together are C 3 -C 4 alkylene, CR 1 =CR 2 -CR 3 =CR 4, CR 1 =CR 2 -O, CR 1 =CR 2 -S, CR 1 =CR 2 -NR 1, CO-O-CO, CONR 1 CO, CO-(o-phenylene)-S, CO-(o-phenylene)-S substituted by one or more D, or are C 1 -C 3 alkylene interrupted by O, S, NR 1 or NCOR 1; provided that at least one of L, L 1, L 2, L 3, L 4, L 5, L 6, L 7, L 8 is other than hydrogen; T 1 and T 2 independently of one another are hydrogen, C 1 -C 20 alkyl, C 5 -C 12 cycloalkyl, C 2 -C 20 alkenyl, C 5 -C 12 cycloalkenyl, C 6 -C 14 aryl, C 1 -C 20 alkyl substituted by one or more D, C 2 -C 20 alkyl interrupted by one or more E, C 2 -C 20 alkyl substituted by one or more D and interrupted by one or more E, C 5 -C 12 cycloalkyl substituted by one or more D, C 2 -C 12 cycloalkyl interrupted by one or more E, C 2 -C 12 cycloalkyl substituted by one or more D and interrupted by one or more E, C 2 -C 20 alkenyl substituted by one or more D, C 3 -C 20 alkenyl interrupted by one or more E, C 3 -C 20 alkenyl substituted by one or more D and interrupted by one or more E, C 5 -C 12 cycloalkenyl substituted by one or more D, C 3 -C 12 cycloalkenyl interrupted by one or more E, C 3 -C 12 cycloalkenyl substituted by one or more D and interrupted by one or more E, or C 6 -C 14 aryl substituted by one or more D; R 1, R 2, R 3, R 4, R a, R b and R c independently of one another have the meaning of T 1; T denotes T 1 or O-T 2; each X is identical and is a single bond, CR a R b, O, S, NR c or NCOR c; D is hydrogen, R 5, OR 5, SR 5, NR 5 R 6, halogen, NO 2, CN, O-glycidyl, O-vinyl, O-allyl, COR 5, NR 5 COR 6, COOR 5, OCOR 5, CONR 5 R 6, OCOOR 5, OCONR 5 R 6, NR 5 COOR 6, SO 3 H or SO 3 M; E is O, S, COO, OCO, CO, NR 5, NCOR 5, NR 5 CO, CONR 5, OCOO, OCONR 5, NR 5 COO, SO 2, SO, CR 5 =CR 6 or R 5 and R 6 independently of one another are hydrogen, C 1 -C 12 alkyl or phenyl; Y is an inorganic or organic anion; and M is an inorganic or organic cation. each L, each L 1, each L 2, each L 3, each L 4, each L 5, each L 6, each L 7 and each L 8 is identical and L, L 1, L 2, L 3, L 4, L 5, L 6, L 7 and L 8 independently of one another are hydrogen, R 1, OR 1, SR 1, NR 1 R 2, halogen, NO 2, CN, NR 1 COR 2, COOR 1, OCOR 1, CONR 1 R 2, OCOOR 1, OCONR 1 R 2, NR 1 COOR 2, SO 3 H, SO 3 M, SOR 1, SO 2 R 1 or are COT; and/ or the pairs L 3 and L 5 together are a single bond, CR a R b, CO, O, S, NR c or NCOR c; provided that L 3 and L 5 together are no single bond, when the respective X denotes a single bond; and/or the pairs L 1 and L 3, L 1 and L, L 5 and L 7 together are C 3 -C 4 alkylene, CR 1 =CR 2 -CR 3 =CR 4, CR 1 =CR 2 -O, CR 1 =CR 2 -S, CR 1 =CR 2 -NR 1, CO-O-CO, CONR 1 CO, CO-(o-phenylene)-S, CO-(o-phenylene)-S substituted by one or more D, or are C 1 -C 3 alkylene interrupted by O, S, NR 1 or NCOR 1; provided that at least one of L, L 1, L 2, L 3, L 4, L 5, L 6, L 7, L 8 is other than hydrogen; T 1 and T 2 independently of one another are hydrogen, C 1 -C 20 alkyl, C 5 -C 12 cycloalkyl, C 2 -C 20 alkenyl, C 5 -C 12 cycloalkenyl, C 6 -C 14 aryl, C 1 -C 20 alkyl substituted by one or more D, C 2 -C 20 alkyl interrupted by one or more E, C 2 -C 20 alkyl substituted by one or more D and interrupted by one or more E, C 5 -C 12 cycloalkyl substituted by one or more D, C 2 -C 12 cycloalkyl interrupted by one or more E, C 2 -C 12 cycloalkyl substituted by one or more D and interrupted by one or more E, C 2 -C 20 alkenyl substituted by one or more D, C 3 -C 20 alkenyl interrupted by one or more E, C 3 -C 20 alkenyl substituted by one or more D and interrupted by one or more E, C 5 -C 12 cycloalkenyl substituted by one or more D, C 3 -C 12 cycloalkenyl interrupted by one or more E, C 3 -C 12 cycloalkenyl substituted by one or more D and interrupted by one or more E, or C 6 -C 14 aryl substituted by one or more D; R 1, R 2, R 3, R 4, R a, R b and R c independently of one another have the meaning of T 1; T denotes T 1 or O-T 2; each X is identical and is a single bond, CR a R b, O, S, NR c or NCOR c; D is hydrogen, R 5, OR 5, SR 5, NR 5 R 6, halogen, NO 2, CN, O-glycidyl, O-vinyl, O-allyl, COR 5, NR 5 COR 6, COOR 5, OCOR 5, CONR 5 R 6, OCOOR 5, OCONR 5 R 6, NR 5 COOR 6, SO 3 H or SO 3 M; E is O, S, COO, OCO, CO, NR 5, NCOR 5, NR 5 CO, CONR 5, OCOO, OCONR 5, NR 5 COO, SO 2, SO, CR 5 =CR 6 or R 5 and R 6 independently of one another are hydrogen, C 1 -C 12 alkyl or phenyl; Y is an inorganic or organic anion; and M is an inorganic or organic cation.