This work aims to emphasise that the common use of acetonitrile (ACN) for non-aqueous redox flow batteries (RFBs) is not a safe and economical option for the community. It is strongly recommended to apply deep eutectic solvents, which, if designed intelligently with the right feedstocks, can outperform acetonitrile at lower costs and also reduce environmental impacts of RFBs significantly. Graphene as electrocatalysts may be replaced by 2D chalcogenides in future investigations.