This work deals with surfactant-free microemulsions (SFME) and is composed of two parts. In the first part these kind of ternary systems were investigated as a possible alternative for toxic extraction solvents that are still in use. In the second part pre-structuring of hydrotropes in water was studied, and its influence on the solubilisation of a third, hydrophobic component. Solvent extraction is widely used as a separation method. With the evolution of green chemistry new solvents are required with properties such as low toxicity and easy separation. SFMEs are considered as possible alternatives due to their better wetting properties and their possibility of solubilisation of hydrophobic components. Such solubilisation properties depend on the formation of supramolecular aggregates that typically occur in such systems. Three systems were investigated for this purpose: oleic acid/solketal/H 2 O, glycerol triacetate/EtOH/H 2 O and triethyl citrate/EtOH/H 2 O. All systems showed pronounced mesoscale structuring near the phase separation border proved by DLS measurements. Ternary system oleic acid/solketal/H 2 O was a “proof of principle system” of a cleavable SFME suitable for green extraction. Recently, it was established that structuring of binary mixtures of short chain alcohols/H 2 O have a significant influence on the solubilisation of hydrophobic compounds such as benzyl alcohol and limonene. Second part of the work was focused on the study of more versatile hydrotropes such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetonitrile (ACN), dioxane, ethanol (EtOH), tert-butyl alcohol (TBA), γ-valerolactone (GVL) and tetrahydrofuran (THF). DLS and conductivity measurements were carried out to demonstrate the presence of structures in the binary and ternary mixtures. surfactant-free