Context Rules! Special Issue on “Physical Organic Chemistry: Never Out of Style”

Recommendations H ow does one explain why the same substrate behaves differently in a round-bottom flask, in a micelle, or on a metal surface�speeding up here, yielding an altered product distribution there?The contexts vary, but the fundamental questions remain.Which chemical entity reacts?How does the catalyst shape the approach of the reactants and the organization of a transition structure?Why does a thermodynamically unstable compound form preferentially?And what is the best way to interrogate the chemical process?Physical organic chemistry answers these questions by identifying relevant chemical species and measuring how populations shift in response to the molecular environment.The transformations matter, as do the methods that reveal the reactive structures, the intermediates, and the transition structures.The studies gathered here make that case.In this Special Issue of The Journal of Organic Chemistry, leading research groups share foundational insights and recent advances across synthetic chemistry, computational modeling, spectroscopy, kinetics, thermodynamics, and the design of catalysts and functional materials.Fundamental research plays an important role in sustainable development.Contributors to this issue demonstrate these principles across a range of systems, describing how structural and environmental factors govern reactivity and selectivity, spanning micelles and metal surfaces, photochemical intermediates and their spectroscopic characterization, speciation and off-cycle states in catalysis, and the re-evaluation of textbook rules through modern analysis.In most cases, theory and experiment work together to identify the key intermediates and the conditions that control their reactivity.Many contributions describe tested or testable predictions for tuning outcomes by shifting equilibria or redesigning the environment.The scope of systems covered�from energy storage materials to CO 2 fixation to quantitative reaction modeling� makes it clear that physical organic methods are applicable across synthetic and materials chemistry and that detailed analysis of structures, equilibria, and rates is a practical route to both mechanistic insight and reaction design.