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The metal−organic framework MIL-101(Cr) is known as a solid−acid catalyst for the solution conversion of biomass-derived glucose to 5-hydroxymethyl furfural (5-HMF). We study the substitution of Cr³⁺ by Fe³⁺ and Sc³⁺ in the MIL-101 structure in order to prepare more environmentally benign catalysts. MIL-101(Fe) can be prepared, and the inclusion of Sc is possible at low levels (10% of Fe replaced). On extended synthesis times the polymorphic MIL-88B structure instead forms.Increasing the amount of Sc also only yields MIL-88B, even at short crystallisation times. The MIL-88B structure is unstable under hydrothermal conditions, but in dimethylsulfoxide solvent, it provides 5-HMF from glucose as the major product. The optimum material is a bimetallic (Fe,Sc) form of MIL-88B, which provides ~70% conversion of glucose with 35% selectivity towards 5-HMF after 3 hours at 140 °C: this offers high conversion compared to other heterogeneous catalysts reported in the same solvent.