Spiropyran has emerged as a versatile molecule for constructing dynamic materials due to its unique structural isomerization response to various stimuli such as light, temperature, metal ions, redox potential, and mechanical stress. This review discusses the synthesis, switching conditions, and applications of dynamic materials where spiropyran is attached to polymers, biomacromolecules, inorganic nanoparticles, and solid surfaces. The materials exhibit fascinating properties where the state of the switch significantly affects the properties of the support. The utility of spiropyran as a switch will likely lead to widespread applications in the near future. The chapter highlights the advantages of covalently attaching spiropyran to supports, including no leaching, improved processability, solvent compatibility, biocompatibility, prevention of MC aggregation, reduced photodegradation, improved fluorescence, and the ability to tailor the behavior of the switch. The support often has a significant impact on the optical properties and isomerization kinetics of the switch. The chapter also covers the synthesis of spiropyran-functionalized polymers, including random copolymers, block copolymers, and polymers with disubstituted spiropyran units. These polymers have been used to create photoresponsive nanoparticles with reversible fluorescence switching, which are useful for localization microscopy and biological imaging. Additionally, the chapter discusses the photocontrol of polymer solubility and volume phase transitions in thermoresponsive polymers, demonstrating the versatility of spiropyran-based materials.Spiropyran has emerged as a versatile molecule for constructing dynamic materials due to its unique structural isomerization response to various stimuli such as light, temperature, metal ions, redox potential, and mechanical stress. This review discusses the synthesis, switching conditions, and applications of dynamic materials where spiropyran is attached to polymers, biomacromolecules, inorganic nanoparticles, and solid surfaces. The materials exhibit fascinating properties where the state of the switch significantly affects the properties of the support. The utility of spiropyran as a switch will likely lead to widespread applications in the near future. The chapter highlights the advantages of covalently attaching spiropyran to supports, including no leaching, improved processability, solvent compatibility, biocompatibility, prevention of MC aggregation, reduced photodegradation, improved fluorescence, and the ability to tailor the behavior of the switch. The support often has a significant impact on the optical properties and isomerization kinetics of the switch. The chapter also covers the synthesis of spiropyran-functionalized polymers, including random copolymers, block copolymers, and polymers with disubstituted spiropyran units. These polymers have been used to create photoresponsive nanoparticles with reversible fluorescence switching, which are useful for localization microscopy and biological imaging. Additionally, the chapter discusses the photocontrol of polymer solubility and volume phase transitions in thermoresponsive polymers, demonstrating the versatility of spiropyran-based materials.