A composition-dependent polymorphism is observed in Y3Rh4Ge13. Y3Rh4Ge13-polymorphs are weakly-coupled BCS-like superconductors. Besides superconductivity, another state-of-the-art property arises from the temperature-dependent characteristics of magnetic susceptibility and electrical resistivity – charge density wave state appearing below Tf = 177 K. The single crystal diffraction synchrotron studies at 100 K (well below Tf) and 300 K (room temperature, also well above Tf) are acquired to prove the structural transition as well as to determine the crystal structure of both low-temperature and high-temperature polymorphic modifications. In situ temperature-dependent (300 K-100 K-300 K) powder diffraction will confirm the evolution of the structural changes on a degree-resolved scale.