Robust bi-directional photoswitching of thiomethyl substituted arylazopyrazoles under visible light.

Mono-ortho- and para-thiomethyl-substituted arylazopyrazoles show substantial absorbance in visible wavelengths, enabling very high to near-quantitative forward and reverse isomerization in DMSO and aqueous solution by visible light. cis isomers display excellent thermal stability (∼3 days, 27 °C). Additionally, these switches possess good photostability and are resistant to reduction by glutathione.