Hydrogen bonding between carboxylic acids and pyridines can be used as a means of chain extension. However, the reversibility of hydrogen bond formation does not allow the chain-extended structure to be fixed, and a temperature-dependent chain length results. Complexation between a tetrapyridyl species and a diacid is shown to counteract the reversibility of the hydrogen bonding. These complexes form thermoreversible three-dimensional supramolecular networks which have properties typical of low molar mass materials at high temperatures but polymeric properties at low temperatures. The complexes exhibited a glass transition and could form fibers from the melt yet exhibited a low-viscosity isotropic liquid at elevated temperatures. Atypically, a complex incorporating a 2,2’,6,6’-tetrasubstituted biphenyl moiety was found to be liquid crystalline.