It is a challenge to develop materials for use in fuel cell applications. Presently we are preparing new perovskite and double perovskite structured compounds being potential candidates for use as anode materials in solid oxide fuel cells (SOFCs). In order to study structure-property relationships at elevated temperature we will use a recently developed in-situ cell to carry out measurements of conductivity during the diffraction experiment. The key objectives are: i) to extract structural information from a range of new compounds, ii) to correlate structure with oxygen ion conducting properties of those compounds.