We have reviewed our recent neutron scattering works on imidazolium-based ionic liquids. Neutron diffraction and quasielastic neutron scattering measurements were performed to investigate both structural and dynamical properties of the ionic liquids. They have characteristic nano-structures that are similar to the layer structure of the smectic A liquid crystalline phase. The motions of the alkyl-chains, ionic groups, and nano-structures were observed in a wide dynamic range over 1 ps to 1 μs.
