Colloidal I-III-VI nanocrystals and their deriva0ves are emerging as eco-friendly next-genera0on materials for light-emiDng and light-harves0ng applica0ons. This symposium will bring together researchers working across synthesis, spectroscopy, theory, and device integra0on of colloidal I– III–VI nanocrystals and related systems to discuss recent advances and challenges in the field. Topics include controlled synthesis strategies for pristine, alloyed, and nonstoichiometric compositions; heterostructures and core-shell architectures; and fundamental studies of defects, excited-state dynamics, and radia0ve and nonradia0ve recombina0on pathways. Emphasis will be placed on structure–property rela0onships that direct whether emission arises from bandedge or sub-gap defect states, and the role of composi0on, surface ligands, and stoichiometry in tuning these behaviors. The symposium will also cover applica0ons in LEDs, luminescent solar concentrators, photocatalysis, solar energy conversion, lasing, and amplified spontaneous emission. Contribu0ons employing advanced spectroscopic approaches to probe charge and energy transfer processes in assembled and hybrid systems are equally encouraged.