A series of comb-shaped fluorene-based poly (arylene ether sulfone nitrile) (CFPESN-x) was synthesized as anion exchange membranes (AEMs). The well-designed architecture of fluorene-based main chains and comb-shaped C8 long alkyl side chains containing quaternary ammonium groups was responsible for the clear microphase-separated morphologies, as confirmed by small angle X-ray scattering and atomic force microscopy. Moreover, nitrile groups on main chains also showed a profound influence on membrane morphology and properties. CFPESN-x exhibited more interconnected ionic domains with increasing the nitrile group content resulting in higher conductivities and anti-swelling property. Then CFPESN-x exhibited high ionic conductivities in the range of 27.1 -91.5 mS cm(-1) from 30 to 80 degrees C and superior ratios of conductivity to swelling ratio at 80 degrees C at moderate IECs. Moreover, CFPESN-x also showed good mechanical properties and thermal stability, and optimizable alkaline stability and single cell performance. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.