Figure shows the GA yield of aDUT-67 and DUT-67 over time, and Figure shows the conversion reached at the final time point. The catalytic activity of aDUT-67 is almost double that of the pristine MOF. To confirm that the improvement is due to enhanced activity of active sites rather than Zr leaching, a control experiment was conducted (Figure ; see Methods for details). The yields after 4 hours were consistent between the main experiment and the control (hot filtration) within experimental error, ensuring no cluster or Zr leaching occurred and that the reaction was purely heterogeneous. Cyclability tests on aDUT-67 over five cycles showed an activation phase during the first three cycles, likely due to defect formation and increased Zr wt.%, as indicated by TGA data showing more missing-linker defects (Figure ). Taking into account the changing Zr wt.% in aDUT-67 in early cycles, the yield increase from cycles 1 to 4 was slightly lower (39% compared to 54% yield gain, Figure ). Despite a decrease in surface area (Figure ), it is evident that the activity of Zr sites increased with increasing density of defects, likely due to reduced steric hindrance from missing-linker defects. Given that the Zr-sites are the actual reaction centers, we calculated conversions based 200 on the mole fraction of Zr in DUT-67 and aDUT-67, derived from TGA data (see Methods).