An organic ionic plastic crystal (OIPC) 2-hydroxyethyltrimethylammonium iodide (choline iodide) as an important component in solid electrolyte is synthesized and applied in dye-sensitized solar cells. It allows relatively rapid diffusion of the redox couple through the plastic crystal phase that is critical to the cell performance. The novel material, utilizing strong quaternary ammonium cation 2-hydroxyethyltrimethylammonium (HETA+) as a cation donor, is treated as matrix in electrolyte. At optimal condictions, the cell gives a short-circuit photocurrent density (J sc), open-circuit voltage (V oc) and fill factor (FF) of 6mAcm−2, 0.69V and 63%, respectively. The corresponding overall conversion efficiency (η) is 2.5%. The results suggest that the OIPC is a promising solid electrolyte material for dye-sensitized solar cells applications.