AbstractSolvent extraction is one of the hydro metallurgical techniques adopted due to its ease for efficient separation of metal ions. The separation and extraction of metals are enabled using privileged metal distribution between the aqueous and organic phase. Commercially available solvent extractants and recently the designer solvents like ionic liquids have gained adequate attention in the area of separation science for the retrieval of different metal ions. Diluents play an important role by ensuring the improved hydrodynamics of the extraction system. The physico‐chemical characteristics of the organic phase solution need to be scrutinized thoroughly in order to optimize the extraction conditions. Investigation on the interaction between extractant and diluent at molecular level is vital for the assessment of extraction efficiency. Density, viscosity, dielectric constant, refractive index, conductivity, and acoustic properties provide evidence on the molecular organizations between these unlike molecules. The aim of this review is to project on the importance of physical, chemical, and thermodynamic properties for fabricating an efficient combination of extractants‐diluents to achieve maximum extraction output.