Raman Spectroscopy. Raman spectra for the parent CuBTC and cycled [EMIM][TFSI]@CuBTC composites were collected on a Renishaw inVia Raman microscope at ×100 magnification using an excitation wavelength of 488 nm with a resolution of 2 cm -1 over the wavenumber region of 100-1650 cm -1 . High temperature spectra were collected in situ using the same spectrometer with an Ar-filled heating chamber placed in the microscope. Heating was done in isothermal steps of 5 K, with an acquisition time of 120 s per step (corresponding to an effective heating rate of 2.5 °C min -1 ).