A class of phenolphthalein anilide based poly(ethersulfone) (PES) block copolymers containing pendent quaternary ammonium (QA) groups was prepared as anion exchange membranes by reaction involving nucleophilic substitution, benzylic bromination, quaternization and anion exchange with hydroxide ions. Hexafluorobenzene (HFB) was utilized as a linkage group between the hydrophobic and hydrophilic oligomer blocks. Nano-phase separated membrane morphology due to block structure of poly (ethersulfone) serves for better management of absorbed water for higher hydroxide conductivity with good thermal, and dimensional stability. The water uptake, swelling ratio, conductivity, and chemical stability of the copolymer membranes were comparatively investigated.