Three natural dyes, i.e., yellow, red, and blue, were extracted from gardenia and used as sensitizers in the assembly of rainbow dye-sensitized solar cells (DSSCs) to harvest light over a wide range of wavelengths. The adsorption characteristics, photovoltaic efficiencies, and electrochemical properties of the rainbow DSSCs were investigated. Adsorption kinetic data for the dyes were obtained in a small adsorption, chamber. The data fitted a pseudo-second-order model. The photovoltaic performance of a photo-electrode with an adsorbed mixture of the three dyes was evaluated from current-voltage measurements.