Ionic liquids (ILs) have been known as a class of green solvent and played an important role in green chemistry in recently years. Materials based on ILs, such as poly(ionic liquid) and polymer/ILs composites, are also widely investigated and possess many unique properties and applications. In this chapter, green solvent IL is reviewed and the responsive behavior of ILs based materials to external stimulus, like ultrasound (US), is introduced. Especially, it is described that FT-IR spectroscopy was effective for analyzing hydrogen bonding in ILs, polymeric ILs and PVA/IL composites. In addition, shear viscosity and viscoelasticity measurement and techniques of two-dimensional correlation and deconvolution are applied to analyze the change of interaction between IL to different substances and US responded behavior.