▎ 摘　　要

NOVELTY - An oligophenylene monomer, is new. USE - The oligophenylene monomer is useful for the preparation of a polymeric precursor for producing graphene nanoribbons useful in an electronic, optical, or optoelectronic device (all claimed). ADVANTAGE - The oligophenylene monomer can be efficiently used in preparing a polymeric precursor used producing improved graphene nanoribbons for an electronic device. DETAILED DESCRIPTION - An oligophenylene monomer of general formula (I). R1 and R2=H, halogen, -OH, -NH2, -CN, -NO2 or a linear or branched, saturated or unsaturated 1-40C hydrocarbon residue, which can be substituted 1- to 5-fold with halogens (F, Cl, Br, I), -OR3, -NR32, -CN and/or -NO2, and where one or more CH2-groups can be replaced by -O-, -S-, -NR4-, -OC(O)- or -C(O)-, or an optionally substituted aryl, alkylaryl or alkoxyaryl residue; R3=H , 1-30C alkyl, 2-30C alkenyl, 2-30C alkynyl, 1-30C haloalkyl, 2-30C haloalkenyl, 2-30C haloalkynyl or 2-30C acyl; R4=H, 1-30C alkyl, 2-30C alkenyl, 2-30C alkynyl, 1-30C haloalkyl, 2-30C haloalkenyl, 2-30C haloalkynyl or 2-30C acyl; and m=0, 1 or 2. INDEPENDENT CLAIMS are: (1) a polymeric precursor for preparing graphene nanoribbons having repeating units of general formula (II); (2) a process for the production of graphene nanoribbons by cyclodehydrogenation of the polymeric precursor; (3) graphene nanoribbons, obtainable by the latter process; (4) a composition comprising one or more graphene nanoribbons dissolved or dispersed in a liquid medium; and (5) an electronic, optical, or optoelectronic device comprising a thin film semiconductor comprising one or more graphene nanoribbons. n=a number from 2-100.