The synthesis of 3-[2-(oxiran-2-yl)ethyl]-1-{4-[(2-oxiran-2-yl)ethoxy]benzyl}imidazolium bis(trifluoromethane)sulfonimide was achieved in seven steps with an overall yield of 63%. This ionic liquid monomer is based on an imidazolium core containing a phenoxy moiety and aliphatic chains with a reactive epoxide at both ends. This imidazolium was obtained by an efficient, reproducible, and scalable synthesis from inexpensive reagents. In the last step, a powerful oxidative agent was successfully used to generate two epoxy functions with only acetone as a byproduct. The monomer structure and intermediates were analyzed by NMR experiments, infrared, and mass spectra. In addition, the thermal properties of the diepoxide were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).