PhotOnline is a free online conference organized by and for young researchers of the SP2P (Photochemistry, Photophysics, and Photosciences) division from the French Chemical Society (SCF). This meeting creates an opportunity for young researchers, such as Ph.D. students and postdoctoral researchers, to present their own research and foster interdisciplinary conversations and further collaboration within the community. This second edition of the PhotOnline 2023 conference is open to international speakers with vast knowledge of the frameworks of SP2P such as chemical synthesis and transformation, fluorescent sensors, electron and energy transfer processes, often studied by advanced spectroscopy and simulation tools.