Their tendency to form host–guest complexes is key to the molecular machines recognized by the 2016 Nobel Prize in Chemistry.
Viologens are used in the negative electrolytes of some experimental flow batteries. Viologens have been modified to optimize their performance in such batteries, e.g. by incorporating them into redox-active polymers.
Viologen catalysts have been reported to have the potential to oxidize glucose and other carbohydrates catalytically in a mildly alkaline solution, which makes direct carbohydrate fuel cells possible.