AbstractTailor-made poly(α-methylstyrene)- and poly(4-methylstyrene)-block-poly(4-vinylpyridine) diblock copolymers with poly(4-vinylpyridine) as the minority component were synthesised via living anionic polymerisation. In bulk they show spherical or cylindrical microphases. From these block copolymers highly-ordered isoporous block copolymer membranes were prepared by combining block copolymer selfassembly and the nonsolvent induced phase separation process (SNIPS). The membrane properties were analysed by water flux and retention measurements. Due to the high glass transition temperatures of the major blocks these block copolymer membranes show a thermal stability up to 150 °C.