A new type of highly temperature stable ionic liquid (IL) with strongly temperature dependent nanostructures is reported. The molecular design relies on the use of a liquid polymer with an ionic liquid headgroup, introducing liquid properties by both the polymeric and the ionic liquid (IL) headgroup. The IL polymers (poly-(isobutylene)s) 3a-3c (PIB-ILs) were prepared by a combination of living carbocationic polymerization (LCCP) and subsequent "click" chemistry for attachment of methylimidazolium (3a), pyrrolidinium (3b), and triethylammonium cations (3c). All three investigated PIB-ILs exhibited pronounced nanostructural organization at room temperature depending strongly on the nature of the anchored cation. Whereas the morphology of the imidazolium-based PIN-IL 3a shows high thermal stability up to the decomposition temperature, order-order (OOT) and lattice disorder-order transitions (LDOT) characteristic for common ionomers could be observed in the case of pyrrolidinium 3b and ammonium-based 3c PIB-ILs. Control of flow behavior as well as adjustable relaxation times from the liquid to the viscoelastic regime can be adjusted by choice of the appropriate IL headgroup.