Recently TEMPOL derivatives are known the possibility of wide potential windows for Redox Flow Batteries(RFBs) as organic catholyte. Herein we report the investigation on electrochemical properties of TEMPOL derivatives. To do this we prepared TEMPOL derivatives and investigated CV results depending on their different functional group. Also the best result of TEMPOL derivatives was applied to RFBs system and measured the VRFBs cell efficiency with TEMPOL Acetate derivative.