The effect of Zr-substitution on the evolution of crystal structure, thermal expansion and the electronic transport properties is reported for La1-xSrxCo0.2Fe0.6Zr0.2O3-delta (0.1 <= x <= 1.0) and La1-xSrxCo0.2Mn0.6Zr0.2O3-delta = 0.1, 0.2, 0.25, 03). La1-xSrxCo0.2Fe0.6Zr0.2O3-delta was found to be single-phase for the compositions investigated. The electrical conductivity of La1-xSrxCo0.2Fe0.6Zr0.2O3-delta demonstrated a maximum for x = 0.5, while the area specific resistance was shown to decrease significantly with increasing Sr-content due to an increased concentration of oxygen vacancies. No signs of oxygen vacancy ordering were observed. The area specific resistance of La0.3Sr0.7Co0.2Fe0.6Zr0.2O3-delta at 600 degrees C is close to an order of magnitude lower than reported values for La0.4Sr0.6Co0.2Fe0.8O3-delta. The series La1-xSrxCo0.2Mn0.6Zr0.2O3-delta was found as multiphaSe materials. The stability of both series is discussed with respect to the red-ox properties of the transition metals. (C) 2017 Elsevier B.V. All rights reserved.