Oxynitrides constitute a vast class of emerging solids to explore new or improved properties analogous to those of oxides. In this perspective we will show recent developments in this area, discussing different groups of structures and materials such as colossal magnetoresistive (CMR), pigments, phosphors, photocatalysts for water splitting and organic molecule degradation, dielectrics, and anodes for lithium batteries, in connection with their preparative methods and crystal chemistry.