That's great in concept. How large would you have to scale up to power turbines to light up a city. This doesn't seem feasible in practical applications like cell phone batteries, since you are transferring thermal heat, rather than electrons through a redox reaction.

Furthermore, the release of that stored solar heat requires catalysis by acid. Sort of reminds me of a glow stick, where you have to crack the internal container containing a secondary chemical to create a reaction to generate light. It's a 1x use product, it isn't reversible. On a larger scale, how to you recapture the pyrimidone, and acid and convert the pyrimidone back to it's dewar form? You have to irradiate the pyrimidone with UV light to break its aromaticity and create a strained bicyclic structure - which means you have to put energy back into the system.

Is the cycle have the UV light/sun create the dewar form, then throw some acid in to generate heat, put the pyrimodone back in the sun and repeat? Mirrors and Solar panels don't produce acid waste while they operate. (Manufacturing might be a different issue.)