Abstract: Fluoranthene derivatives of the general formula I where the symbols have the following meanings: R1, R2, R3, R4, R5 are each hydrogen, alkyl, an aromatic radical, a fused aromatic ring system, a heteroaromatic radical or —CH?CH2, (E)- or (Z)-CH?CH—C6H5, acryloyl, methacryloyl, methylstyryl, —O—CH?CH2 or glycidyl; where at least one of the radicals R1, R2 and/or R3 is not hydrogen; X is an alkyl radical, an aromatic radical, a fused aromatic ring system, a heteroaromatic radical or a radical of the formula (I?) or an oligophenyl group; n is from 1 to 10 or, in the case of X=oligophenyl group, 1-20; with the proviso that R1, R2, R3 and X are not at the same time phenyl when R4 and R5 are hydrogen.