The most stable oxidation states of cerium are +4 and +3. Cerium(IV) compounds have been extensively utilized as convenient and effective one-electron oxidants for a variety of transformations. However, the trivalent state is the most common oxidation state for cerium, and cerium(III) chloride heptahydrate (CeCl3·7H2O) is the most common source of Ce3+ commercially available. For this, CeCl3 has been widely used in a large number of applications realized in academic and industrial laboratories. Furthermore, in producing organic molecules, there are increasing requirements for green and efficient promoters, with particular attention to several environmentally friendly6 and atom-economical organic transformations. The use of promoters, then, has received increasing attention, as it allows great advantages, such as energy savings, waste minimization, and high-purity delivering products, and recent reports have highlighted the applications of cerium trichloride as a green and efficient Lewis acid in modern organic synthesis, and they are powerful approaches to realize synthetic procedures with great chemical efficiency and reduced environmental impact.