Two series of sulfonated multiblock copoly(ether-ketone)s containing phthalazinone ether ketone and fluorene ether ketone moieties have been synthesized successfully by two-step polycondensation. The water uptakes of the copolymers with varying sized sulfonated poly(phthalazinone ether ketone) block as hydrophilic blocks are moderate. In this series, polymer 10a gave the proton conductivity of 1.20 x 10(-3) S/cm with IEC of 1.03. The water uptakes of the copolymers with varying sized sulfonated poly(fluorene ether ketone) blocks as hydrophilic blocks are high than 300%. These copolymers showed better proton conductivity. The copolymers with sulfonated poly(phthalazinone ether ketone) blocks had strong alcohol resistance at refluxing temperature. Whereas the copolymers containing sulfonated poly(fluorene ether ketone) hydrophilic blocks were dissolved in methanol and ethanol. The cast films of the title ionomers were transparent, ductile, and flexible. Moreover, these copolymers demonstrated greatly improved oxidative and thermal stabilities. Especially, the copolymers comprising sulfonated poly(phthalazinone ether ketone) hydrophilic blocks and poly(fluorene ether ketone) hydrophobic blocks is a promising proton exchange membrane material for proton exchange membrane fuel cell used methanol or ethanol as fuel. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 1100-1110, 2010