Electrofluorochromic molecules share the unique property that their fluorescence changes as a function of their oxidation state. This makes them interesting from a fundamental perspective as molecular dyads are designed and synthesized to tune the interplay of electrochemical and luminescent properties of molecules. Electrofluorochromic systems also find applications in sensing because a fluorescent signal can be detected with high sensitivity. Moreover, in the recent years the interest in redox-switchable fluorescent polymers has strongly increased due to their applicability in display devices. Here, we review electrofluorochromic molecules and polymers; we emphasize their structures and functional principles and point to specific applications.