This chapter provides an overview and critical evaluation of the techniques of localized protonic coupling. The double inhibitor-titration approach provides strong evidence for localized coupling or energy transfer domains. The experiments involved are technically relatively straightforward, requiring only the measurement of the rates of phosphorylation. The uncoupler/energy transfer inhibitor experiments in which the observation that one ionophore per thylakoid or per chromatophore cause a certain amount of uncoupling is used in support of the delocalized chemiosmotic coupling concept. The harmonization of double inhibitor-titration protocols within the framework of metabolic control theory might constitute a particularly rigorous and rewarding approach to this problem. Respiration-driven H + translocation method is described in the chapter. The translocation of protons and sometimes of other ions is measured with ion-selective electrodes and calibrated with anaerobic standard solutions. Ion-distribution methods are widely used to measure the chemiosmotic membrane potential, which dominates the protonmotive force (pmf). The rate of transmembrane field-driven secondary ion transport is a function of both any transmembrane potential and the native permeability coefficient.