Phthaloylchitosan‐based gel polymer electrolytes were prepared with tetrapropylammonium iodide, Pr₄NI, as the salt and optimized for conductivity. The electrolyte with the composition of 15.7 wt.% phthaloylchitosan, 31.7 wt.% ethylene carbonate (EC), 3.17 wt.% propylene carbonate (PC), 19.0 wt.% of Pr₄NI, and 1.9 wt.% iodine exhibits the highest room temperature ionic conductivity of 5.27 × 10⁻³ S cm⁻¹. The dye‐sensitized solar cell (DSSC) fabricated with this electrolyte exhibits an efficiency of 3.5% with J_SC of 7.38 mA cm⁻², V_OC of 0.72 V, and fill factor of 0.66. When various amounts of lithium iodide (LiI) were added to the optimized gel electrolyte, the overall conductivity is observed to decrease. However, the efficiency of the DSSC increases to a maximum value of 3.71% when salt ratio of Pr₄NI : LiI is 2 : 1. This cell has J_SC, V_OC and fill factor of 7.25 mA cm⁻², 0.77 V and 0.67, respectively.