An optical device with favorable characteristics is provided. An optical device with low driving voltage is provided. An optical device with low power consumption is provided. The optical device includes a first electrode, a second electrode, an active layer, and a carrier-transport layer. The active layer is positioned between the first electrode and the second electrode. The active layer contains a first organic compound and a second organic compound, the first organic compound is represented by General Formula (G1), and the second organic compound is represented by General Formula (G2-1). The carrier-transport layer is positioned between the second electrode and the active layer and the thickness of the carrier-transport layer is greater than or equal to 10 nm and less than or equal to 300 nm.