Nonaqueous unimolar solutions of lithium perchlorate (LiClO 4 ) and lithium trifluoromethanesulfonate or triflate (LiCF 3 SO 3 ) in γ-butyrolactone (γBL) mixed in (a) 1:1 and (b) 3:2 volume ratios yield mixed salt electrolytes with good conductivity performance with σ 2 5 approaching 10 - 2 S cm - 1 . Addition of 10 wt.% of poly(methylmethacrylate) (PMMA) to these liquid electrolytes manifests in producing highly viscous gel electrolytes with η 2 5 in the range of 10 4 -10 5 cSt and σ 2 5 greater than 10 - 3 S cm - 1 . Conductivity and viscosity studies reveal that PMMA plays an insignificant role in controlling the conduction mechanism in gel electrolytes, as they tend to retain the liquid-like behaviour. Also, the dimensional strength bestowed to gels by the polymer stimulates their use in electrochromic windows (ECWs). Inconsequential variation of σ over the operational temperature range of an ECW renders them to be ideal candidates for the same.