Processes involving the photoexcited states of matter, or excitons, underpin some of today’s most important and diverse scientific advances, from solar cells, to quantum technologies via photosystems and catalysis. The discussion meeting brought together world-leaders from traditionally separate fields to share views on the fundamental science, exploitation and characterisation of excitons, aiming to generate radical advances in exciton science and technology. This special issue gathers key papers from the different fields, spanning quantum phenomena to fundamental understanding of exciton delocalisation.