It is important to develop viable technologies for efficient hydrogen (H2) production and carbon dioxide (CO2) conversion to realize the future supply of clean energy and reduction of global CO2 concentration. Herein, we report a series of carbamate-substituted ruthenium-dithiolate complexes 1–3, [Rux(CO)y(μ-SCH(NCO2(C(CH3)3))CH2CH2S)] (x=2, 3, 6 and y=6, 9, 20), which can effectively catalyze the reversible formic acid-carbon dioxide (FA-CO2/H2) cycle that can be used to convert CO2 and produce H2. Complex 2 effectively dehydrogenates FA to produce H2 with an unprecedented turnover frequency (TOF) of 1.15×106 h−1 under conditions of sunlight irradiation. Under conditions of high temperature and pressure, complex 3 hydrogenates CO2 to FA with a high initial TOF of 1.02×106 h−1, resulting in an efficient FA-CO2/H2 cycle. These results can potentially help provide the platform for the development of technologies that can be used in future to produce clean energy and control environmental threats.