Provided are graphene nanoribbon precursors comprising repeated units of the general formula (I) in which R1, R2 are each H, halogen, —OH, —NH2, —CN, —NO2 or a hydrocarbyl radical which has 1 to 40 carbon atoms and may be linear or branched, saturated or unsaturated and mono- or poly-substituted by halogen (F, Cl, Br, I), —OH, —NH2, —CN, and/or —NO2, where one or more CH2 groups may also be replaced by —O—, —S—, —C(O)O—, —O—C(O)—, —C(O)—, —NH— or —NR—, in which R is an optionally substituted C1C40-hydrocarbyl radical, or an optionally substituted aryl, alkylaryl or alkoxyaryl radical.