In this study, oxygen release/consumption behavior of calcium manganese-based oxides (CaMn_1–xB_xO₃, where B: Cu, Fe, Mg and x = 0.1 or 0.2) used in a chemical looping oxygen uncoupling (CLOU) application was investigated. The effect of B-site dopants such as Fe, Mg, and Cu on the oxygen release behavior was also investigated with the aim to use these materials in thermal energy storage (TES). Previous literature studies about CLOU performance of doped calcium manganites were taken into consideration for dopants selection. Calcium manganite-based oxides have been used in chemical looping oxygen uncoupling (CLOU) applications owing to their oxygen release behavior to the gas phase. Studies have revealed that calcium manganite-based oxides show a promising nonstoichiometry over a range of temperatures and oxygen partial pressures, which makes them useful for thermochemical energy storage applications. However, the related literature studies have been mainly focused on their nonstoichiometric characteristics related to temperature and oxygen partial pressure and thermodynamic properties. In this work, thermal analysis and fluidized bed tests were carried out as complementary techniques. CaMn_0.8Cu_0.2O₃ showed the highest oxygen release performance in fluidized bed tests, while CaMn_0.9Mg_0.1O₃ had the best cyclic stability overall among the samples used in the study.