A heat-induced drastic switching from a transparent smectic A (SmA) phase to a light-scattering nematic (N*) one was achieved for a (homeotropically oriented polymer network (HOPN)/side chain type liquid crystalline polymer (SCLCP)/liquid crystals (LCs)/chiral dopant) quaternary composite. In the case that the composite was rapidly cooled from the heat-induced light-scattering N* phase to the SmA one, the SmA phase exhibited a strong light-scattering state. When an a.c. electric field above the threshold valve was applied to the composite in the light-scattering state, the strongly light-scattering SmA phase was changed into a transparent SmA one. Both the transparent and the light-scattering SmA states could be maintained for a long time (similar toyears) at room temperature. Thus, the composite with thermally addressable and electrically erasable characteristics was newly proposed.