Thermoelectric devices are capable of converting thermal energy directly into electrical energy. Large-scale applications of the technology requires materials that are composed of earth-abundant elements. This has led us to investigate synthetic analogues of copper iron sulphide minerals. The structures of Mooihoekite and Talnakhite are related to that of Chalcopyrite, differing in the 3D superstructure produced by ordering of Cu, Fe and vacancies. Physical property data show anomalies in their temperature dependence in the region where DSC data suggest structural transitions occur. We seek to exploit the capabilities of a novel sample cell to carry out an in-situ powder neutron diffraction study to determine the key electrical properties of resistivity and Seebeck coefficient simultaneously with the collection of structural data through the phase transitions.