Electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) gains more and more interest due to its wide range of applications. The present review encompasses the various domains of charge transfer reactions in biphasic systems, with some emphasis on certain studies that marked the advances of electrochemistry at ITIES and that, in a noticeable manner, have been presented in large majority at the ISE meetings during the last two decades. These studies, as well as some subjects in which our recent research interest is concerned, are used here to describe the fundamental aspects of charge transfer reactions at liquid/liquid interfaces and to outline their various applications. This overview presents the methodologies offered by the ITIES in the fields of amperometric sensors, solvent extraction, pharmacokinetics, thermo-electricity and solar energy conversion, and the accent is put on the perspectives of their potential development in the coming years.