CSZM compounds were synthesized by dry chemistry route with 5, 10, and 15% dopant of Mg dopants in the Ce 0.8−2x Sm 0.2 Zrx Mgx O2−d, {x = 0.05, 0.1 & 0.15}. The newly investigated materials were physically, chemically, and electrochemically studied and have shown promising results. The CSZM was crystalized in a fluorite structure with a pure cubic phase in a space group Fm3m and cell parameter a = 5.401742 °A and theoretical density from 7.6 to 8.9 after firing in the air with a final temperature of 1400 °C. Characterization of the structure and indexing of electrolyte materials were made after X-ray diffraction (XRD) testing. A Scanning electron microscope (SEM) morphological analysis was used to examine the microstructure details. Electrochemical impedance spectroscopy (EIS) measurements were performed from 400 °C to 700 °C which show the highest conductivity value of 1.0461 × 10+1 S/cm at 700 °C. In comparison, the minimum value was 2.7329 × 10−2 S/cm at 400 °C, and the total activation energy (Ea°A) was found to be 0.6865 eV under 5% H2/Ar.