molecular switch

https://doi.org/10.1351/goldbook.08842
Molecule that can be reversibly switched between two or more stable states in response to a change in, e.g., its microenvironment (pH, the presence of a ligand, temperature etc.), illumination or electric current.
Note:
Molecules undergoing photoinduced reversible cis-trans isomerization or switching between redox state or protonation states (pH indicators) are examples of molecular switches.
Source:
PAC, 2022, 94, 15. (Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)) on page 38 [Terms] [Paper]