Abstract
Increases in hydrogen selectivity of more than 100% compared with the most selective ladder polymer of intrinsic microporosity (PIM) reported to date are achieved with self‐polymerized A‐B‐type ladder monomers comprising rigid and three‐dimensional 9,10‐dialkyl‐substituted triptycene moieties. The selectivities match those of materials commercially employed in hydrogen separation, but the gas permeabilities are 150‐fold higher. This new polymer molecular sieve is also the most selective PIM for air separation.