Herein, we introduce a comprehensive investigation that unveils the major processes underlying the observed mismatch, quantifying their relative contributions and unpacking the fundamental mechanisms responsible for this phenomenon. We focus on wavelength-dependent selectivity of distinct microenvironments within a bulk solution and reaction kinetics for reversible reactions. We elucidate these contributions on the example of a specific [2+2]-photocycloaddition, with analytical modelling used to quantify this reversible process, and synthesis of a set of tethered chromophores to investigate the effects of wavelength-dependent excited-state lifetimes on photochemical reactivity.