In the advent of a transition from utilizing fossil fuels to renewable energy, redox flow batteries (RFBs) are recognized as one of most promising battery technologies to integrate renewable energy sources (e.g., solar and wind). Although traditional vanadium (V) RFBs and Zn-Br2 inorganic RFBs are established technologies, they suffer from several major techno-economical drawbacks that prevent them from extensive applications in large-scale energy storage. To address the challenges encountered by existing inorganic RFBs, organic redox flow batteries have been recently developed for sustainable and economical large-scale energy storage. The presentation will primarily cover our efforts in developing high performance aqueous organic redox flow batteries (AORFBs) utilizing a variety of rationally designed highly water soluble redox active molecules including viologen, ferrocene, and TEMPO. In addition, we will discuss our most recent work on non-aqueous organic redox flow batteries (NAORFBs).