Cu2ZnSnS4 (CZTS) is a solar cell material of great interest. However the material whenfabricated, although of high symmetry, contains substantial defect concentration and a highdegree of atomic mixing on different crystallographic sites. A lack of knowledge regarding thestructure is currently hampering progress on this material. X-ray measurements have shown aniondisplacement changes begin around 420 K with a phase transition between the low-temperaturekesterite structure and a high-temperature sphalerite structure at 1149 K. In the region 1136-1161K a two-phase region occurs with both phases coexisting around the first order phase transition.We propose to undertake high-resolution neutron powder diffraction study to fully characterise thematerial from 300 K to 1200 K using HRPD.