A 1 mM solution of MGHOH in 2:1 MeCN/water was irradiated with UV light (λexc = 254 nm) under rapid stirring, resulting in a pH jump from 7.0 to 10.8 over the course of 5 min (Figure , green trace). Upon removal of the light source, the solution pH decreased to 8.7 over the next 5 min. Thus, MGHOH undergoes significant but not complete photodissociation in response to UV light and partial recombination in the dark suggesting its promise for the development of photoreversible CO2 capture.