9,10-Bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene polymers consisting of an oligomeric or polymeric compound of the general formula I where R 1 to R 7: are each independently hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, haloalkyl groups, haloalkoxy groups, cycloalkyl groups, cycloalkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, aralkyl groups, carboxylic acid groups, sulphonic acid groups, amino groups, monoalkylamino groups, dialkylamino groups, nitro groups, cyano groups, hydroxyl groups, alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, carboxylic ester groups, carboxamide groups, sulphonic ester groups, thiol groups, halogen atoms or a combination of these groups or atoms, particular preference being given to hydrogen atoms as at least five of the R 1 to R 7 substituents and to non-hydrogen atoms, preferably halogen atoms, alkyl groups, alkoxy groups, cyano groups and/or nitro groups, as zero to two of the R 1 to R 7 substituents, R 8 to R 11: are each independently hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, haloalkyl groups, haloalkoxy groups, cycloalkyl groups, cycloalkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, aralkyl groups, amino groups, monoalkylamino groups, dialkylamino groups, nitro groups, cyano groups, hydroxyl groups, alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, carboxylic ester groups, carboxamide groups, sulphonic ester groups, thiol groups, halogen atoms or a combination of these groups or atoms, where the R 8 and R 9 substituents or the R 10 and R 11 substituents may form a further ring consisting of five to seven atoms (the ring may be aromatic, heteroaromatic or nonaromatic; if the ring is nonaromatic, it may consist of various groups, for example alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, haloalkyl groups, haloalkoxy groups, cycloalkyl groups, cycloalkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, aralkyl groups, amino groups, monoalkylamino groups, dialkylamino groups, alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, carboxylic ester groups, carboxamide groups, sulphonic ester groups; more preferably, R 8 to R 11 are the same and are alkyl groups, such as typically methyl groups or ethyl groups, alkylthio groups, such as methylthio groups, or ethylthio groups and thiol groups), X: is an organic group which is formed by polymerization reaction from a group consisting of an organic double bond, an organic triple bond, an oxirane or an aziridine, or is an organic group which is formed by a polymer-analogous reaction, n: is an integer greater than or equal to 2. R 1 to R 7: are each independently hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, haloalkyl groups, haloalkoxy groups, cycloalkyl groups, cycloalkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, aralkyl groups, carboxylic acid groups, sulphonic acid groups, amino groups, monoalkylamino groups, dialkylamino groups, nitro groups, cyano groups, hydroxyl groups, alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, carboxylic ester groups, carboxamide groups, sulphonic ester groups, thiol groups, halogen atoms or a combination of these groups or atoms, particular preference being given to hydrogen atoms as at least five of the R 1 to R 7 substituents and to non-hydrogen atoms, preferably halogen atoms, alkyl groups, alkoxy groups, cyano groups and/or nitro groups, as zero to two of the R 1 to R 7 substituents, R 8 to R 11: are each independently hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, haloalkyl groups, haloalkoxy groups, cycloalkyl groups, cycloalkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, aralkyl groups, amino groups, monoalkylamino groups, dialkylamino groups, nitro groups, cyano groups, hydroxyl groups, alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, carboxylic ester groups, carboxamide groups, sulphonic ester groups, thiol groups, halogen atoms or a combination of these groups or atoms, where the R 8 and R 9 substituents or the R 10 and R 11 substituents may form a further ring consisting of five to seven atoms (the ring may be aromatic, heteroaromatic or nonaromatic; if the ring is nonaromatic, it may consist of various groups, for example alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, haloalkyl groups, haloalkoxy groups, cycloalkyl groups, cycloalkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, aralkyl groups, amino groups, monoalkylamino groups, dialkylamino groups, alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, carboxylic ester groups, carboxamide groups, sulphonic ester groups; more preferably, R 8 to R 11 are the same and are alkyl groups, such as typically methyl groups or ethyl groups, alkylthio groups, such as methylthio groups, or ethylthio groups and thiol groups), X: is an organic group which is formed by polymerization reaction from a group consisting of an organic double bond, an organic triple bond, an oxirane or an aziridine, or is an organic group which is formed by a polymer-analogous reaction, n: is an integer greater than or equal to 2.