This symposium provides an interdisciplinary platform for discussing new developments in the understanding of the roles that nanocrystal surface chemistry and defects play in mophology and function. Topics will encompass development of new synthetic routes that control the suface chemistries and defect structures of nanocrystals, either directly or through exchange processes. Experimental and theoretical tools that illuminate surface and defect structures will be discussed, as well as applications of surface and defect chemistry in a broad range of applications including the design of surface cataytic sites, and in energy conversion applications including solar cells.