Novel semifluorinated poly(arylene ether) copolymers are prepared by aromatic nucleophilic substitution reactions between 4-phenoxy-2,3,5,6-tetrafluorobenzonitrile and various bisphenols in the presence of potassium carbonate as a base at room temperature. The molecular weights and molecular weight distribution of poly(arylene ether) copolymers are determined by the substitution groups in 4-phenoxy moiety and the reactivity of bisphenols. The highest molecular weights of copolymers are achieved with base to phenol ratio of 1.5 at room temperature, but the molecular weights of copolymers decreases with increasing reaction temperature and decreasing the base concentration. The copolymers synthesized from 4-phenoxy-3-(trifluoromethyl)-2,3,5,6-tetrafluorobenzonitrile/4-phenoxy-3,5-bis(trifluoromethyl)-2,3,5,6-tetrafluorobenzonitrile and 4,4′-(hexafluoroisopropylidene)diphenol shows high molecular weights (M n = 2.0–2.7 × 104) and low molecular weight distributions (M w/M n = 1.25–1.4) compared to other substituted groups in 4-phenoxy moieties of PFBN and other bisphenols combinations. The poly(arylene ether) copolymers synthesized from bisphenol-A exhibit high thermal stability compared to 4,4′-(hexafluoroisopropylidene)diphenol copolymers and the char yield of copolymers are >40 %.