AbstractElectrochemical switching of luminescence color, that is, electrofluorochromism, has received increasing attention because of its extensive applications. In this study, we investigate the combination of a luminescent EC molecule and a blue luminescent molecule to achieve electrochemical control of luminescence color by controlling the energy transfer through an electrochromic reaction. We employed a functional leuco dye (Yellow‐1), which shows yellow coloration and green emission by electrochemical oxidation, and 2,5‐bis(5‐tert‐butyl‐benzoxazol‐2‐yl)thiophene (BBT), which shows strong blue luminescence upon photoexcitation. Using this combination, the blue photoluminescence of the BBT molecule can be electrochemically modulated by the EC reaction of the Yellow‐1 molecule, allowing the control of the luminescence color between blue and green emissions through electrochemical reactions.