SBF derivatives having the following formula: SBF-X wherein: with m = 0, 1, 2 or 3; p = positive integer, preferably 1, 2 or 3, with (p + 1) being the valency of K; n = positive integer, preferably 1, 2 or 3; L: is the same or different and independently represents C, PR, S, or S=Y; Y: is the same or different and independently represents O or S; K: is the same or different and independently represents a chemical bond or a group selected from O, S, N, NR (2-p), CR (3-p), CR (3-p) (C 6 H 4) (p+1), with (2-p) and (3-p) being a positive integer including zero; alkane, substituted alkane, alkene, substituted alkene, alkyne, substituted alkyne, aromatic or R substituted aromatic, heteroaromatic or R substituted heteroaromatic or a group resulting from benzene and non benzene, monocyclic and polycyclic hydrocarbons, which can be bivalent, trivalent or of higher valency; or a combination of two, three or four of the above mentioned groups;SBF: spiro-compound of formula: R, A, B, C, D: is the same or different and independently represents H, deuterium, F, Cl, Br, I, CN, a linear, branched or cyclic alkyl or alkoxy chain with 1 to 40 carbon atoms, whicht can be substituted by R 1 and in which one or more non-neighbouring carbon atoms can be replaced by N-R 1, O, C=O, CO-O, CO-NR 1, -CR 1 =CR 1 - or -C≡C- and in which one or more H-atoms can be replaced by F or CN, or an aromatic or heteroaromatic ring system with 5 to 40 aromatic ring atoms, which can be substituted by deuterium, F, Cl, Br, I, CN or one or more substituents R 1, or a combination from two, three or four of these systems; two or more substituents R can form a further monocyclic or polycyclic aliphatic or aromatic ring system with each other; R 1: is the same or different and independently represents H or an aliphatic or aromatic hydrocarbon rest with 1 to 20 C-atoms;wherein the following compounds are excluded: wherein L, A, B, C and D have the same meaning as above and Ar is the same or different from one another and independently represents a bivalent aromatic or heteroaromatic ring system with 2 to 40 carbon atoms, wherein one or more hydrogen atoms can be replaced by F, Cl, Br or I and which can be substituted by one or more non-aromatic substituents R; two or more substituents R, A, B, C or D on the same ring as well as on different rings, can form a further monocyclic or polycyclic aliphatic or aromatic ring system with each other. m = 0, 1, 2 or 3; p = positive integer, preferably 1, 2 or 3, with (p + 1) being the valency of K; n = positive integer, preferably 1, 2 or 3; L: is the same or different and independently represents C, PR, S, or S=Y; Y: is the same or different and independently represents O or S; K: is the same or different and independently represents a chemical bond or a group selected from O, S, N, NR (2-p), CR (3-p), CR (3-p) (C 6 H 4) (p+1), with (2-p) and (3-p) being a positive integer including zero; alkane, substituted alkane, alkene, substituted alkene, alkyne, substituted alkyne, aromatic or R substituted aromatic, heteroaromatic or R substituted heteroaromatic or a group resulting from benzene and non benzene, monocyclic and polycyclic hydrocarbons, which can be bivalent, trivalent or of higher valency; or a combination of two, three or four of the above mentioned groups;SBF: spiro-compound of formula: R, A, B, C, D: is the same or different and independently represents H, deuterium, F, Cl, Br, I, CN, a linear, branched or cyclic alkyl or alkoxy chain with 1 to 40 carbon atoms, whicht can be substituted by R 1 and in which one or more non-neighbouring carbon atoms can be replaced by N-R 1, O, C=O, CO-O, CO-NR 1, -CR 1 =CR 1 - or -C≡C- and in which one or more H-atoms can be replaced by F or CN, or an aromatic or heteroaromatic ring system with 5 to 40 aromatic ring atoms, which can be substituted by deuterium, F, Cl, Br, I, CN or one or more substituents R 1, or a combination from two, three or four of these systems; two or more substituents R can form a further monocyclic or polycyclic aliphatic or aromatic ring system with each other; R 1: is the same or different and independently represents H or an aliphatic or aromatic hydrocarbon rest with 1 to 20 C-atoms;wherein the following compounds are excluded: wherein L, A, B, C and D have the same meaning as above and Ar is the same or different from one another and independently represents a bivalent aromatic or heteroaromatic ring system with 2 to 40 carbon atoms, wherein one or more hydrogen atoms can be replaced by F, Cl, Br or I and which can be substituted by one or more non-aromatic substituents R; two or more substituents R, A, B, C or D on the same ring as well as on different rings, can form a further monocyclic or polycyclic aliphatic or aromatic ring system with each other.