Covalently self-assembled polymer nanocapsules (NCs) basedon cucurbit[6]uril have been previously prepared and their applications inpayload delivery and bioimaging have been demonstrated, showing significantpotentials. However, the preparation of these NCs often requires laborious andtedious multistep reactions, including a low-yield conversion ofperhydroxycucurbit[6]uril to perallyloxycucurbit[6]uril, subsequent photo-polymerization of perallyloxycucurbit[6]uril with dithiol linkers, and twoadditional steps of treatment to remove disulfide loops and create cationicsulfoniums. Herein, we report a novel, facile approach leading to cucurbit[6]-uril-based polymer NCs via direct alkylation of perhydroxycucurbit[6]uril witha ditopic linker, thereby saving significant time and efforts, which may lead tosignificant expansion in investigations of these unique materials in variousapplications, particularly biomedical sciences. As a proof of concept, we havefurther demonstrated that a photosensitive therapeutic payload, such as chlorine6, may get encapsulated inside the NCs for improved, targeted photodynamic therapy against cancer cells.