The elaboration of new porous materials possessing reactive sites and large pores with high surface areas, which are able to capture and release guest molecules, is the subject of intensive research activity.[1] The particular interest in hybrid metal–organic framework (MOF) porous materials stems from their chemical versatility compared with classical porous solids.[1, 2] It is possible to tune the pore size, shape, and connectivity by subtle modifications of the inorganic moiety and the organic linker molecules.[1, 2] They are currently attracting high fundamental and industrial interest across a wide domain of applications, including gas adsorption, liquid separation, and drug delivery.[1, 3]

In addition to this large variety of chemical and structural features, a fascinating property arises with some MOFs, which relates to their dynamic micropores being able to respond to external stimuli such as pressure, temperature, and guest molecules.[4–9] Such dynamic frameworks are topical as they open potential applications for high-performance molecular recognition and high selectivity for guest inclusion and release. This “breathing” phenomenon is currently associated with a structural transition between two states separated by energy barriers higher than the thermal vibration energy.[10] The transformation can reversibly induce an expansion or a contraction of the cell volume corresponding to atomic displacements of up to 10. Such solids include Cu2 (pzdc) 2-(dpyg)(pzdc= pyrazine-2, 3-dicarboxylate, dpyg= 1, 2-di (4-pyridyl) glycol) and some of the MIL (Materials of Institute Lavoisier) series, which exhibit a magnitude of breathing from 25 up to 230% in cell volume variation upon adsorption/desorption of various guest molecules.[9–11] However, although experimental techniques can detect the signature of such