COST is the acronym (in French) for "European Cooperation in the Field of Scientific and Technical Research". It is a framework for international research and development cooperation, allowing to coordinate national research at European level. COST does not fund research as such, but coordination of research. COST includes as member states countries from the European Union, and a number of other European countries.

The COST Action will focus on setting up a network of European researchers active in the field of the novel semiconductor III-N-V gain materials also known as dilute nitrides and indium-rich GaInN. Dilute nitrides, including GaInNAs, GaNP, and GaInNAs-P have emerged from conventional III-V semiconductors by the insertion of nitrogen into the group V sub-lattice, and indium-rich GaInN by the insertion of indium into GaN.

These processes have a profound effect on the electronic properties of host materials and allow a wide range of options for band structure engineering, which is expected to lead to novel devices for displays, data storage, transmission, solar cells, photodynamic therapy, surgery, terahertz devices and gas sensors operating in a wavelength range, extending from 0.3 to 3.0 micrometer. The Action covers material growth and characterisation, theory, device modelling and fabrication, as well as device performance and characterisation.