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Homogeneous catalysis occurs when the catalyst and reactants are present in the same macroscopic phase, most commonly as molecularly dispersed species in a liquid solution. The catalyst may be a neutral molecule, coordination complex, ion, or ion pair, but it undergoes a sequence of elementary steps that regenerates the catalytically active species. For metal complexes, these steps can include ligand association or dissociation, oxidative addition, migratory insertion, and reductive elimination; homogeneous organocatalysis instead proceeds through covalent or noncovalent activation by an organic catalyst. The defining criterion is phase and molecular dispersion, not catalyst composition: both metal and metal-free catalysts can be homogeneous. Molecular catalysts that transform carboxylic acids illustrate the breadth of substrates addressed by homogeneous cycles ^[1]. The concept is distinguished from heterogeneous catalysis, where the catalyst forms a separate phase and reaction occurs at an interface, although immobilized or biphasic systems can combine features of both classes ^[2].