The self-assembly of inorganic open framework structures has blossomed during the 1990s. Following a short historical summary of the held, the main features of the major classes of microporous materials-cyanide open-frameworks, chalcogenides, polychalcogenides and thio-pnictates-are described. The review concludes with a brief discussion of microporous structures of the main group (e.g. K8Sn25, see figure) and organic tecton frameworks.