File Name : figure_s1.tif Caption : figure s1. azo@mdesy-1 mounted on a cryoloop with paratone-n oil at the p11 beamline: a) before data collection and b) after data collection, showing the leaking of an unidentified liquid. File Name : figure_s2.tif Caption : figure s2. a) asymmetric unit of mdesy-1 showing a h2mim laying on a symmetry element. b) packing of mdesy-1 along the c axis, showing h2mim ions inside of the pores. File Name : figure_s3.tif Caption : figure. s3. thermal ellipsoid plot (50% of probability) for mdesy-1 at 100k. File Name : figure_s4.tif Caption : figure. s4. thermal ellipsoid plot (50% of probability) for mdesy-2 at 100k. File Name : figure_s5.tif Caption : figure. s5. thermal ellipsoid plot (50% of probability) for mdesy-1 in p-1 space group at room temperature. File Name : figure_s6.tif Caption : figure. s6. thermal ellipsoid plot (50% of probability) for azobenzene at room temperature. File Name : figure_s7.tif Caption : figure. s7. thermal ellipsoid plot (50% of probability) for azo@mdesy-1 at room temperature. File Name : figure_s8.tif Caption : figure s8. images of the 3-d mdesy-1, view down the a-c) a, b and c axis. neutral 2mim ligands are drawn in yellow, btc ligands in light green and cobalt ions are drawn as purple polygons. hydrogen atoms and counter ions were omitted for clarity. File Name : figure_s9.tif Caption : figure s9. images of the 2-d mdesy-2, view down the a-c) a, b and c axis. neutral 2mim ligands are drawn in yellow, btc ligands in light green and cobalt ions are drawn as purple polygons. hydrogen atoms and co-crystallising water were omitted for clarity. File Name : figure_s10.tif Caption : figure s10. magnetic characterisation of mdesy-1 and mdesy-2 measured at 1 t in the 3 – 400 k temperature range. temperature dependence of dc magnetic moment for a) mdesy-1 and b) mdesy-2. inverse molar magnetic susceptibility (χm-1) vs temperature, including linear extrapolation to the zero level of a possible ferromagnetic ordering, for c) mdesy-1 and d) mdesy-2. the χmt vs temperature plot for e) mdesy-1 and f) mdesy-2. File Name : figure_s11.tif Caption : figure s11. magnetic characterisation of mdesy-1 and mdesy-2 measured at 2 t in the 3 – 350 k temperature range. temperature dependence of dc magnetic moment for a) mdesy-1 and b) mdesy-2. inverse molar magnetic susceptibility (χm-1) vs temperature, including linear extrapolation to the zero level of a possible ferromagnetic ordering, for c) mdesy-1 and d) mdesy-2. the χmt vs temperature plot for e) mdesy-1 and f) mdesy-2. File Name : figure_s12.tif Caption : figure s12. asymmetric unit cell of a) mdesy-1 in p-1 space group and b) azo@mdesy-1. File Name : figure_s13.tif Caption : figure s13. a) and b) optical images of mdesy-1 at two different orientations, using transmission mode. optical images of mdesy-1 at c) room temperature (17°c) and 130 °c after d) 30 seconds and e) >1 min. File Name : figure_s14.tif Caption : figure s14. optical images of azobenzene at a) room temperature (17 °c) and b) 68 °c. File Name : figure_s15.tif Caption : figure s15. b) uv-vis spectra of the release of azobenzene in ethanol from mdesy-1 in a 2 month period, b) uv-vis spectra of azobenzene solution at different concentration used for the calibration curve and c) calibration curve used to calculate the concentration of released azobenzene. File Name : figure_s16.tif Caption : figure s16. a) pxrd pattern of azo@mdesy-1 before and after the release of azobenzene. diffraction images of a single crystal of azo@mdesy-1 b) before and c) after release of azobenzene. File Name : figure_s17.tif Caption : figure s17. calculated voids in azo@mdesy-1, with azobenzene molecules omitted during the calculation. the red circle highlights a constricted region within the channel.