Heavy polar molecules are sensitive probes of physics Beyond the Standard Model. However, uncontrolled external electromagnetic fields pose challenges to achieving precise and accurate measurements. Minimizing susceptibility to these fields is therefore critical. In this talk, I will present our recent demonstration of clock transitions engineered to realize robust symmetry violation searches in the polyatomic molecule YbOH. Sensitivities to external fields can be suppressed by orders-of-magnitude while preserving high sensitivity to the electron electric dipole moment (eEDM). We perform Ramsey measurements on these clock transitions and observe suppression of electric and magnetic sensitivities by at least a factor of 700 and 200, respectively, and demonstrate the robustness of their coherence against large electromagnetic field fluctuations. We further engineer “field sensing transitions” to perform precise measurements of the electromagnetic environment in-situ, another critical feature for highly accurate measurements. This approach is broadly applicable to diverse molecular species and states, including those with complex nuclei and those that are compatible with state-of-the-art cooling and trapping techniques, thereby offering the potential to significantly improve experimental sensitivity to a wide range of New Physics.