Nowadays ionic liquids are in the focus of scientific interest owing to their attractive properties. In this context, a series of amino acid-based ionic liquids (AAILs; EmimGly, EmimAla, EmimPro, and EmimSer) were synthesized and characterized by NMR and elemental analysis. Thermophysical properties such as density and viscosity were measured in the temperature range of T = (293.15 to 353.15) K and refractive index in the temperature range of T = (293.15 to 333.15) K. The thermal expansion coefficient values were calculated from the acquired experimental density values for T = (293.15 to 363.15) K. A thermogravimetric analyzer (TGA) was used to investigate the thermal degradation behavior of synthesized ionic liquids. © 2011 American Chemical Society.