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. Electronic impedance spectroscopy (EIS) measurements were achieved from 400 °C to 700 °C showing the highest value of conductivity of 1.0461 x 10+1 S/cm at 700 °C while the minimum value was 2.7329 x 10-2 S/cm at 400 °C and the total activation energy was found (Ea) 0.6865 eV under 5% H2/Ar.