We're celebrating Dugan's recent JACS paper on copper-catalyzed photocycloaddition reactions by doing a Back 2 Basics episode on photocycloadditons that is really just an episode on that paper with a little bit of Woodward Hoffmann rules thrown in for good measure. But what is a podcast for besides self-promotion anyway? We return to some of our favorite topics, including X-ray spectroscopy and transient absorption, and discuss how a combination of spectroscopic techniques can be used to deduce photochemical reaction mechanisms involving transition metals. We also ask ourselves how a single methylene group can drastically change the fate of a molecule and how a single pandemic can drastically change the fate of a research project.