Enhancing optical absorption of metal-organic frameworks for improved visible light photocatalysisElectronic supplementary information (ESI) available: Details of the synthesis, photocatalytic tests, X-ray diffraction data, N2 adsorption isotherms, DRIFTs, NMR and TRMC traces. See DOI: 10.1039/c3cc46398b

NH 2 -MIL-125(Ti) has been post-synthetically functionalized with dye-like molecular fragments. The new material (methyl red-MIL-125(Ti)) exhibits improved light absorption over a wide range of the visible spectrum, and shows enhanced photocatalytic oxidation activity under visible light illumination. The consequences of functionalization and the bottlenecks in MOF photochemistry are studied in detail. NH 2 -MIL-125(Ti) functionalized with dye-like moieties exhibits improved light absorption and enhanced photocatalytic activity under visible light illumination.