Disc-shaped objects can be induced to form columnar assemblies whether their scale is tens of Angstroms (molecular), tens of nanometers (macromolecular or supramolecular), hundreds of nanometers (colloidal) or tens of microns ('manufactured' platelets). The last couple of years have seen rapid progress in the development of conducting columnar systems and in controlling the orientation of discotic mesophases. The first serious commercial development has also emerged. Fuji Film Company has perfected and marketed optical compensating films based on cross-linked nematic discogens with controlled hybrid orientation. (C) 2002 Elsevier Science Ltd. All rights reserved.