A new sol-gel polymerisable ionic liquid 1-(2-(2-methoxyethoxy)ethoxy)ethyl)-3-(3-(trimethoxysilyl)propylimidazolium iodide was synthesised with the aim of preparing an I-/I-3(-) redox electrolyte. The processes of hydrolysis and condensation were followed first in acidic and basic conditions using ATR IR and Si-29 NMR spectroscopy. The IR bands at 1100 and 1126 cm(-1), together with the prevailing T-3 signal, showed that more branched silsesquioxane structures formed under basic catalysis. The formation of silsesquioxane structures was also followed in situ using two FT-IR techniques, i.e., transmission and reflection-absorption mode. The conductivity of the basically catalysed electrolyte initially reached 4.3 x 10(-3) S/cm but stabilised at 1.2 x 10(-4) S/cm after condensation. The presence of I-3(-) species was proven by the appearance of v(s)(I-3(-)) mode at 111 cm(-1) in micro Raman spectra and 295 and 370 nm peaks in UV-vis absorption spectra. Finally, the electrolyte was applied in a hybrid electrochromic device that displayed persistent colouring/bleaching during 4240 cycles tested. (C) 2012 Elsevier Ltd. All rights reserved.