In this paper we report the synthesis, structure and optical properties of three analogues of the cyanide Prussian blues, the thiocyanate frameworks M III [Bi(SCN) 6 ]; M = Fe, Cr and Sc, each of which is strongly coloured. We find that these materials form isotypic structures with large octahedral tilts and demonstrate that Cr[Bi(SCN) 6 ] can reversibly take up guests such as water.