The growing global demand for clean energy underscores the limited efficiencies of current renewable technologies, positioning thermoelectric materials as promising candidates for recovering waste heat by converting it into electricity. This project aims to develop and understand rare-earth ternary tellurides as high-performance thermoelectric materials, leveraging their intrinsically low thermal conductivity due to strong phonon scattering by heavy atoms, and high electrical conductivity arising from small band gaps. Building on our recent discovery of a new structure type for Eu-containing telluride, we will investigate the Eu-M-Te system, including solid solutions and explore related compounds with Yb-version. The project combines synthesis and structural characterization by X-ray diffraction with theoretical calculations and collaborative measurements of thermoelectric transport properties, including Seebeck coefficient and electrical and thermal conductivities. This systematic approach will establish structure–property relationships and guide the design of novel thermoelectric materials for efficient waste-heat recovery.