Monitoring the thiol peak by real-time FTIR confirms the rapid polymerization kinetics typical in neat thiolene photopolymerization systems, achieving 63% thiol conversion within 10 seconds with 5 mW/cm2 light intensity (Figure ). The resulting materials were found to be free-standing, glassy, tough, and transparent films, allowing us to readily handle and flex the films at ~200 µm film thickness (scheme 1B).