Polymer matrices can be combined with metal-organic frameworks (MOFs) to enhance their performance for CO2 separation. However, it is challenging to find compatible interactions between MOFs and polymers for this purpose. Now, an international team of scientists has developed a simple strategy to incorporate zirconium-based MOFs into a polymer matrix via covalent bonds. The resulting membranes show excellent gas separation performance, stability, and tolerance to harsh conditions, helping erode current barriers for industrial applications.