Post-synthetic functionalisation of a reduced amine cage with an ionic liquid functionalised aldehyde via aminal formation led to the successful formation of an organic cage decorated with ionic liquid functionality, [RCC1-IM][NTf2]6. This cage was initially isolated as an amorphous material, but exhibited melting behaviour over 55-90 °C, and on subsequent quenching exhibited a glass transition and could be processed into a transparent glassy state. Furthermore, the material could be reprocessed into its original non-glassy amorphous state. The assynthesised amorphous solid [RCC1-IM][NTf2]6 showed a CO2 uptake three times that of solid [Ald-IM][NTf2] (218 ± 2.8 µmol/g vs 76 ± 1.3 µmol/g), with both the liquid and glass exhibiting similar uptakes. The porosity of the system was further supported by molecular dynamics simulations which demonstrated that the observed experimental gas uptake is due to the porosity of the [RCC1-IM][NTf2]6 system, as opposed to the transient void space inherent to the IL structure of the system.