The aim of TPX4 is to demonstrate the feasibility of two new types of electron spectro-microscopies: Time- Resolved Cathodoluminescence Excitation spectroscopy (TR-CLE) and High-Resolution Low Energy Electron Microscopy (HRLEEM). Both ally extreme spatial, energy, and temporal resolutions needed to tackle current challenges in nanosciences. TPX4 relies on the development and use of a new and unique pixelized direct electron detector combining sub-ns temporal resolution and high flux to achieve both TR-CLE and HRLEEM. This ambitious goal will be explored by a consortium of leading experts in instrumentation development for applications of electron microscopy and spectroscopy.