The hexa-4-dodecyloxybenzoyl derivative1of azacrown[18]-N6was originally reported to have a ‘tubular’ mesophase on the basis of its large central ring and 6-fold symmetry. Starting in the mesophase, annealing of1under a cover slip results in formation of a new crystalline phase that melts directly to an isotropic liquid at the temperature previously observed for the mesophase to isotropic transition. Thus the phase behaviour of1is kinetically controlled. The analogous hexa-3,4-bisdodecyloxybenzoyl derivative2of azacrown[18]-N6has no kinetic limitations to its phase changes and has an enantiotropic columnar liquid crystalline phase. We have synthesized side chain copolysiloxanes with a (CH2)11spacer and 75–84 per cent by weight of the same 4-dodecyloxybenzoyl-[18]-N6mesogen. The polysiloxanes also display a liquid crystalline phase.