be a two-step process, since the separated liquids need specific mechanical treatments such as sonication or gas bubbling to return to the initial emulsion form, [8,9] restricting the practical applications. Moreover, the switchable emulsifiers need to be specially designed according to the physical and chemical properties of the host/guest liquids and switching triggers, which makes this method complicated, time consuming, and expensive. Finally, although it has been demonstrated that self-emulsification methods can produce emulsions with small droplet size, i.e., sub-micrometer, without any mechanical energy input, these processes typically require high concentration of surfactants and are not reversible. [14][15][16] An ideal switchable emulsion should fulfill several requirements. First, the guest liquid should be able to be emulsified in the host medium without the need of a specific emulsifier, since the presence of surfactants would compromise the purity of the involved liquids and potentially decrease the performance of the system in its active form. Second, for high reproducibility and reliability, the system should be capable of reversibly producing droplets of uniform size so that every single droplet in the emulsion performs its particular function in the same way. Third, the system should be able to undergo rapid and infinitely reversible on-off switching without any mechanical treatment. In order to realize this, the host and the guest liquids would need to be semimiscible with a degree of miscibility that could be modulated through physical parameters, such as temperature of the guest material. Since semimiscibility requires a mild hydrophobic interface between the two constituents, nonaqueous systems such as oil-in-oil emulsions seem to be appropriate candidates. Yet, oil-in-oil emulsions are usually unstable due to the low surface tension at the oil-oil interface, for instance, ≈3 mN m −1 for hydrocarbon and silicon oils. [17] Stabilizing oil-in-oil emulsions without the use a specifically designed stabilizer is still a challenge. [18] In this paper, we propose a method to fabricate highly stable switchable emulsions that fulfill the requirements mentioned above. The method consists in mixing silicon oil with a semifluorinated liquid crystal (LC) that display two different smectic phases (SmA and SmE) when decreasing temperature from the isotropic phase. We show that emulsification and demulsification processes occur at the smectic A and isotropic phases respectively, enabling fast switching between the two states via temperature. The elasticity and chemistry of the LC guarantees the stability of the emulsified state without the use of any surfactant. Interestingly, we observe two different kinds of A structurally reversible smectic liquid crystal (LC) emulsion made of semifluorinated rod-type molecules in silicon oil, which is controlled by simple heating and cooling, is presented. Without adding any kind of additives, such as surfactants, polymers or emulsifiers, and without using any special t...