After screening several solvents of varying polarities and sizes, acetonitrile-exchanged 1as was taken forward, as MeCN reliably yields a narrow-pore material which has partially closed, and MeCN was previously used as a solvent of choice in solution-based postsynthetic halogenation of MOFs. This material is herein known as 1np (np = narrow pore) on which all further analyses will be based (SI, Section S5). Following further activation under vacuum at 150 °C for 20 h, 1 H NMR spectroscopic analysis of digested samples indicates 1.5 moles of DMF per Sc3O SBU remain in the pores of 1np, and likely explains why a fully closed structure has not been achieved under these conditions. The presence of residual DMF is further confirmed using elemental analysis, where the measured nitrogen content of 3.23% wt correlates well with the value calculated (3.20% wt) from the formula [Sc3O(C4H2O4)3(H2O)2(OH)]‧(C3H7NO)1.5. TGA measurements were carried out in air, to understand the thermal stability of 1 and further probe the solvent content. 1 exhibited a high thermal stability, with degradation of the framework occurring at 460 °C, resulting in a residual mass of 31.0% wt when normalised to remove contribution from adsorbed water below 100 °C. This is concordant with an expected Sc2O3 residue of 31.5% for the above formula predicted by elemental analysis and NMR spectroscopy.