Ti-MOF (MIL-125-NH2, Ti8O36H34N6C48) and the inorganic glass (IG, 70%P2O5-20%Na2O-10%Na2SO4) were synthesised following a slight modification to the reported procedures (see Methods in the Supporting information). Ti-MOF was obtained as a yellow microcrystalline powder (Figure ). The MOF particles' size and shape were analysed by scanning electron microscopy (SEM) (Figure ) and the formula (Ti8O8(OH)4(a-BDC)6) containing small amount of solvents was confirmed by CHN analysis (Table ). Thermogravimetric analysis (TGA) of the activated Ti-MOF showed that it decomposed at Td = 380 ºC (Figure ). 70%P2O5-20%Na2O-10%Na2SO4 glass was obtained as a transparent glass chunk (Figure .c). It was ball milled at 30 Hz for 30 min and stored in dry acetone (Figure ). These phosphate-based glasses are composed of PO4 tetrahedral groups classified using the Q n terminology, where n is the number of bridging oxygen atoms per polyhedra (Figure .d). The amorphous nature of the IG was confirmed by PXRD which displayed a diffraction pattern typical of phosphate-based glasses (Figure ). Differential scanning calorimetry (DSC) of the IG showed a Tg at 178 ºC (Figure ), lower than the MOF Td and so this glass should be thermally compatible with the Ti-MOF to form a composite. Tg is the minimum temperature necessary to form the more viscoelastic phase of the IG. Samples from the compositional series of composites [(Ti-MOF)x(IG)1-x] (where 100x is the wt% of Ti-MOF) were prepared using different weight percentages of the two constituents. They were synthesised following a slight modification to the reported procedure that consisted of ball milling both materials at 20 Hz for 5 minutes to form a physical mixture ((Ti-MOF)x/(IG)1-x). This was then pelletised at 0.074 GPa and the pellets were heated under vacuum at 180 ºC for 30 minutes. These pressure and temperature parameters were optimised to obtain cohesive pellets by utilising the flow of the IG, whilst maintaining the Ti-MOF structure and avoiding any partial decomposition. Sample weight percentages of Ti-MOF were 15%, 25%, 50% and 75%, which resulted in the [(Ti-MOF)0.15(IG)0.85], [(Ti-MOF)0.25(IG)0.75], [(Ti-MOF)0.50(IG)0.50] and [(Ti-MOF)0.75(IG)0.25] composites, respectively. Every synthetic step of these materials was monitored by PXRD (Figure , S8-S9); higher amounts of Ti-MOF in the mixture, resulted in higher intensities of the Bragg peaks from the Ti-MOF structure. After pelletisation, the Bragg peak intensities decrease, but are then maintained after thermal treatment for compositions containing 25, 50 and 75% of Ti-MOF loads (Figure -12, Table ). However, for the 15% sample, extra peaks located at 22.1 and 26.2 º were observed, which were not indexed in the Pawley refinement of the pellet and physical mixture (Figure ). They are from a new titanium phosphate phase formed during the mechanical mixing of the inorganic glass and the Ti-MOF (Figure ). This might be a consequence of the reactivity of the PO4 units at ambient temperature in phosphate-based glasses containing a high load of P2O5, in this case 70%. CHN analysis of the pristine MOF and the composites were carried out to compare to the calculated one to check their formula (Table ). FTIR was also performed to check the vibrational modes of both components (Figure ). SEM images at the surface and within the bulk of the composites revealed a smooth surface with some small microcracks (Figures ). The number of cracks is higher in the [(Ti-MOF)0.50(IG)0.50] and [(Ti-MOF)0.75(IG)0.25] composites due to the agglomeration of the MOF-crystallites into domains, and the inability of the glass to form a homogeneous mixture at the surface. However, bulk analysis in all cases showed that the glass matrix was able to embed even high loadings of MOF (Figure .a). This indicates a homogeneous composite formation (Figures ). Energy dispersive X-ray (EDX) analyses were carried out at five different composite areas at the surface and within the bulk to determine the percentage of P and Ti, and showed homogeneous distributions of both elements (Figures ). Mapping demonstrated different size domains at the surface (Figures ) and the bulk (Figures ), minor cracks were visible between domains. The TGA of the composites (Figure ) shows that there are no major weight losses before 300 ºC, confirming the absence of partial decomposition of the MOF components. DSC analyses show a broad feature between 50 and 150 ºC, ascribed to water desorption at the first upscan (Figure .b, S33-S40). This occurs because the phosphate-based glasses are highly hygroscopic, especially when they contain more than 50% of P2O5. However, the second upscans of composites and physical mixtures containing 15 and 25% of Ti-MOF show a Tg feature occurring at ~130 ºC. This is far below the pristine glass Tg (178 ºC) (Figure ). This likely occurs due to the partial depolymerisation of the glass network with the presence of water upon heating. DSCs from the composite and the physical mixture containing 50% of the Ti-MOF show in the first upscans a smaller broad peak associated with the presence of water and in the second two processes at 130 and 178 ºC (Figure ). This reinforces the hypothesis that the presence of water disrupts the glass network during heating. However, a Tg was not identified in the second upscans of the physical mixture and composite containing 75% of Ti-MOF, likely due to the extremely small amount of the glass in the mixture (Figure ).