The discrete molecular nature of porous organic cages (POCs) has allowed us to direct the formation of
crystalline materials by crystal engineering. It has also been possible to create porous amorphous solids
by deliberately disrupting the crystalline packing, either with chemical modification or by processing.
More recently, organic cages were used to form isotropic porous liquids. However, the connection
between solid and liquid states of POCs, and the glass state, are almost completely unexplored. Here, we
investigate the melting and glass-forming behaviour of a range of organic cages, including both shapepersistent
POCs formed by imine condensation, and reduced and synthetically post-modified amine
POCs that are more flexible and lack shape-persistence. The organic cages exhibited melting and
quenching of the resultant liquids provides molecular glasses. One of these molecular glasses exhibited
improved gas uptake for both CO2 and CH4 compared to the starting amorphous cage. In addition,
foaming of the liquid in one case resulted in a more stable and less soluble glass, which demonstrates
the potential for an alternative approach to forming materials such as membranes without solution
processing.