Following the successful three organizations we are very happy to announce the 4th International Symposium on Materials for Energy Storage and Conversion (mESC-IS 2018) to take place 11-13 September 2019 in Mugla. The symposium as before will provide a forum for discussion in recent progress made in three major activity areas, namely batteries, fuel cells and solid state hydrogen storage The symposium will have a fair balance of plenary sessions covering cross-cutting issues and the state of the art reviews and parallel sessions with contributed papers and poster presentation.  The symposium will just  follows an international summer school with the same name, (mESC-ISS 2019).