Nowadays, in situ/operando electron microscopy is a rapidly growing field due to the implementation of nanotechnology towards the fabrication of greatly improved, stable and more flexible sample holders. Furthermore, data collection, analysis and recording of dynamic information is becoming increasingly faster. Recent advances include, for example, the use of microelectromechanical systems (MEMS) based chips for in situ transmission electron microscopy. The capability to perform multiple measurements while simultaneously analysing corresponding structural, chemical, or even electronic structure changes in functional and nano- materials at different length scales are opening exciting new opportunities at the forefront of modern materials science research. This symposium intends to review progress on in situ/operando TEM and SEM experiments that apply heating, cooling, electrical biasing, and mechanical testing to induce and probe phase transformations.