We report the liquid crystalline (LC) assembly and lower critical solution temperature (LCST) properties of wedgeshaped block copolymer (BCP)/1-alkyl-3-methylimidazolium tetrafluoroborate ([CnMIM][BF4], n = 2, 4, 6) complexes (1-3) depending on the alkyl chain length of the ionic liquids (ILs). In contrast to the crystalline BCP, all of the ionic samples showed LC phases. 1 with [C2MIM][BF4] exhibited a hexagonal columnar phase, and 3 with [C6MIM][BF4] exhibited a gyroid phase. Interestingly, a temperature-dependent transformation from columnar phase to gyroid phase was revealed for 2 with [C4MIM][BF4]. The phase difference may be explained by the supramolecular shape change that was dependent on the alkyl chain length of the ILs. The LCST behavior was characterized using the differential scanning calorimetry, turbidity observations, and the X-ray diffraction techniques. Notably, the primary d-spacing began to decrease at the clouding temperature (T-c). 3 showed the highest T-c at 130 degrees C, which is greater than the temperature of the orderto-disorder transition. The results demonstrate that the subtle variation in the IL structure affects the morphological and LCST properties. (C) 2017 Wiley Periodicals, Inc.