The low viscosities of the linear sulfites dimethyl sulfite and diethyl sulfite are suggesting an investigation of their suitability as low viscosity co-solvents for ethylene carbonate based electrolytes. In this study, electrochemical performances at graphitic anodes and conductivities in the temperature range −60 to +60°C are presented. Comparisons with the linear carbonates dimethyl carbonate and diethyl carbonate, which have been currently used as low viscosity solvents in lithium ion batteries, are made.