The synthesized compositions La_0.7Ca_0.3−xSr_xMnO₃ show their potential in thermal control application. The crystal structure, surface morphology, and the temperature dependence of resistivity, infrared spectra and emissivities for the compositions are reported. All of the synthesized compositions exhibit the characteristics of perovskite structure and of metal–insulator transition. Crystal structure of the compositions changes from the orthorhombic to the rhombohedral structure with increasing doping level (x). The infrared properties of compositions can be automatically adjusted basing on variation in temperature. In the temperature range 97–373 K, the variation amplitude of infrared emissivity exceeds 0.5. The potential application of the compositions in thermal management is discussed.