The design and development of agonistsselectively targeting thyroid hormone receptorβ (TRβ) and TRβ mutants remain challenging tasks. In this study, we first adopted the strategy of breaking the “His-Phe switch” to solve two problems, simultaneously. A structure-based design approach was successfully utilized to obtain compound 16g, which is a potent TRβ agonist (EC50: 21.0 nM, 85.0% of the maximum