High ionic liquid content (up to 97 wt%) supramolecular ionogels are prepared via host-guest interactions between a host of beta-cyclodextrin (beta-CD) and a guest of bis-imidazolium ionic liquid, Bis-C-12(mim)Br, in a room temperature ionic liquid, 1-propyl-3-methylimidazolium iodide (PMII). The driving force for the formation of supramolecular ionogels is attributed to the intermolecular hydrogen bonding of imidazolium cations. The ionic conductivity and gel-to-sol phase transition temperature of the prepared supramolecular ionogels can be tuned by the ratio of Bis-C-12(mim)Br(guest) to beta-CD (host), as well as the content of PMII solvent. The prepared supramolecular ionogels are applied as quasi-solid-state electrolytes for dye-sensitized solar cells (DSSCs), which show an efficiency of 4.62% under a simulated air mass 1.5 solar spectrum illumination at 100 mW cm(-2) and excellent long-term stability. (C) 2015 Elsevier Ltd. All rights reserved.