Thermally reversible nanostructured thermosetting materials are prepared for the first time by modification of an epoxy resin with 5 wt.-% of an amphiphilic polystyrene-block-poly(ethylene oxide) block copolymer (PSEO) and 30 wt.-% of a low-molecular-weight liquid crystal, 4'-(hexyl)-4-biphenylcarbonitrile (HBC). The epoxy system modified with 5 wt.-% PSEO amphiphilic copolymer self-assembles into spherical microdomains with a size distribution between 32 and 45 nm in diameter. Under the same conditions, the modification of an epoxy system with 5 wt.-% PSEO and 30 wt.-% HBC leads to a micro-phase separated PS-rich domains embedded in a HBC phase. The morphology of this nanostructured thermosetting system consists in a higher amount of spherical microdomains of PSEO/HBC with the size distribution between 40 and 75 nm in diameter. This implies that the separation of the PS-rich phase provokes the separation of the liquid crystal and allows one to obtain a novel thermally switchable smart material.