Four novel organosilicon-based iodides, trimethylsilylmethoxy ethoxytrimethylammonium iodide (TMSC 1 EN 1 I), (2-trimethylsilylmethoxy) ethoxytrimethylammonium iodide (TMSC 1 EN 2 I), (2-(2-(2-trimethylsilylmethoxy)ethoxy)ethoxy) ethoxytrimethylammonium iodide (TMSC 1 EN 3 I) and trimethylsilylmethy diethylmethylammonium iodide (TMSPCI), were designed and synthesized. 1 H NMR and 13 C NMR spectra were recorded to confirm the synthesis of pure products. The organosilicon-based ionic liquids were investigated as the sole iodide sources for electrolytes in dye-sensitized solar cells (DSSCs). The best solar cell efficiency of 3.70% was achieved with TMSC 1 EN 1 I (bearing one ethylene oxide segment between silicon and ammonium cation) as the sole iodide source in MPN-based electrolyte at AM 1.5 full sunlight (100 mW/cm 2 ).