Abstract: Chromatic systems and structures are presented that operate without external electrical supply, which enable changes in color or transparency of a substrate material, such as glass. Various configurations provide a mechanism to activate an oxidation-reduction reaction in a chromatic material, so as to change from transparent to opaque or from one color to another. These structures may be used in applications from windows for buildings and homes, camera lenses, automotive displays and windows, mobile device displays, and other applications where chromatic change is desired.