Phenothiazines have seen widespread use as stable electron-donating organic compounds with generally stable oxidized states, making them an amenable core for functionalization toward electrochemical energy storage applications. With phenothiazine itself as a starting material, functionalization of the 3, 7, and 10 positions is facile, providing options to modify redox potentials and improve stability in both the neutral and singly oxidized (radical cation) states.  In one to three steps, we can create highly soluble, stable derivatives that are suitable for applications requiring the donation of one or two electrons. We have observed thousands of hours of overcharge protection in lithium-ion batteries and more recently have moved into testing these species as the electro-active materials for non-aqueous redox flow batteries. This presentation will focus on the synthesis and characterization of new derivatives, highlighting new results in which we found that a liquid phenothiazine that can be prepared in one step from commercially-available starting materials can serve as an electron donor and solvent, dissolving some lithium salts to concentrations of at least 1 M.