An oligophenylene monomer of general formula (I) wherein R1 and R2 are independently of each other H, halogene, —OH, —NH2, —CN, —NO2 or a linear or branched, saturated or unsaturated C1-C40 hydrocarbon residue, which can be substituted 1-to 5-fold with halogene (F, Cl, Br, I), —OH, —NH2, —CN and/or —NO2, and wherein one or more CH2-groups can be replaced by —O— or —S—, or an optionally substituted aryl, alkylaryl or alkoxyaryl residue; and m represents 0, 1 or 2.