The project is aimed at the development of new sulfide electrocatalytic and fluorescent materials, characterization of their crystal and local structures. Two approaches will be used to search for new materials: i) synthesis under high pressure – high temperature conditions; ii) solution based synthesis for optimizing prospective compositions. To monitor phase transformations in the reaction mixture in situ X-ray diffraction data will be collected under high pressure and high temperature at synchrotron facility (Hasylab), followed by high pressure synthesis under optimal conditions. Crystal structures of the discovered compounds will be analyzed by X-ray diffraction; local and surface structures will be probed by X-ray absorption spectroscopy (XANES and EXAFS). Voltammetry combined with the differential electrochemical mass spectroscopy (DEMS) will be applied to understand mechanisms of charge transfer across solid-liquid interface for non-oxide materials. The new compounds with wide band gap will be used as hosts for the rare-earth activated phosphors.