This work showcases the utility of switchable materials.Included are a switchable room-temperature ionic liquid, a switchable solvent, a switchable heterogeneous catalyst system, and a switchable gel.First, the switchable ionic liquid 2-butyl-1,1,3,3-tetramethylguanidium methylcarbonate is fully investigated.Its use in a complete chemical process (including reaction, separation, reformation, and recycle) is demonstrated with several reactions.Furthermore, its potential use for bitumen separation and purification and SO2 capture/isolation are discussed, and preliminary data is presented.Next, piperylene sulfone (PS), a switchable solvent, is synthesized and fully characterized.Anionic nucleophilic substitution reactions were performed in PS, the products were isolated in high yields, and then the PS was reformed for reuse.Then, we designed an immobilized fluorous microphase system that uses F-MonoPhos to induce high enantioselectivities as a switchable heterogeneous catalyst system.Finally, stable reversible polyethyleimine-CO2 gels have been synthesized with 1-octanol.Our findings indicate that PEI-1200/octanol/CO2 gels have potential as a possible drug carrier matrix for transdermal delivery applications.