​Photo frame(work): The first spectroscopic evidence of metal-organic frameworks (MOFs) acting as photocatalysts has been obtained. Isoreticular MOFs act as efficient photocatalysts in the photooxidation of propylene. The band gap energy can be tuned by changing the organic linker. Among the MOFs tested, the 2,6-naphthalenedicarboxylic acid based IRMOF was the most active, showing a higher activity than ZnO.