Photochemical reactions are typically designed around the intrinsic properties of chromophores and substrates, while additives such as Lewis acids and electrolytes are often assumed to play secondary or purely ground-state roles. However, our recent work demonstrates that these species are not innocent bystanders, but can actively reshape excited-state reactivity through electrostatic and coordination effects. This lecture highlights the non-innocent roles of Lewis acids and electrolytes through three case studies. First, in photoinitiation, Lewis acids introduced as polymerization control agents are shown to red shift photoinitiators and perturb their excited-state landscapes and subsequent reactivity. Second, in photoenolisation Diels–Alder reactions, Lewis acids commonly used as conventional cycloaddition catalysts are found to strongly influence the photoenolisation step itself, with significant consequences for efficiency and selectivity that have not previously been appreciated. Third, in photoredox catalysis, emerging experimental results reveal that specific electrolytes can substantially improve reaction yields, highlighting an underexplored role for ionic environments in modulating light-driven transformations. Together, these studies demonstrate how electrostatic environments created by Lewis acids and ions can be harnessed to control excited-state processes, providing new opportunities and guiding principles for the design and optimization of photochemical reactions.