Polyacrylonitrile (PAN) based gel polymer electrolytes (GPEs) consisting of Plasticizers: ethylene carbonate (EC) and propylene carbonate (PC) and different compositions of tetrabutylammonium iodide (TBAI) salt were investigated, aiming to apply in dye-sensitized solar cells (DSSC). The interactions between the polymer and EC/PC were analyzed by EIS, FTIR, XRD and DSC techniques. EIS study shows that the GPE containing 20% TBAI has lowest bulk impedance and highest ionic conductivity (2.4 × 10−3 S.cm−1) as well as a diffusion coefficient of 1.9 × 10−7 cm2.s−1. The interactions between nitrile (-CN) groups in the polymer and the ether oxygen (-O-) groups in the EC/PC were observed. The GPEs are applied to fabricate dye sensitized solar cell (DSSC) for photovoltaic studies. The DSSC with GPE containing 20% TBAI has highest efficiency of 4.2% with short circuit current density of 16.85 mA/cm2, open circuit voltage of 549 mV and fill factor 0.45.