CO2‐based materials: Metastable CO2/diene‐based lactones, which were prepared by the palladium‐catalyzed telomerization of CO2 and dienes, easily undergo aerobic radical homo‐polymerization to give novel CO2‐rich polymers. This two‐step reaction set‐up expands the potential applications of CO2‐based copolymers by adding innovative compositions, structures, and properties.