A benzoindole-based compound represented by Formula 1 below, a dye including the benzoindole-based compound, and a dye-sensitized solar cell including the dye: is prepared at a low cost, has a high molar absorption coefficient, and high photoelectron conversion efficiency, as compared to a conventional ruthenium dye. The benzoindole-based dye is an organic dye including an N-aryl electron donor and an acidic functional group an electron acceptor.