Chemical reactions with incompatible mechanisms (such as nucleophilic reactions and electrophilic reactions, cationic polymerization and anionic polymerization) are usually difficult to perform simultaneously in one-pot. In particular, synchronous cationic-anionic polymerization has been an important challenge in the field of polymer synthesis due to possible coupling termination of both chain ends. We recently found that such terminal couplings can be significantly inhibited by a bismuth salt with a strong nucleophilic anion (e.g., BiCl