Based on a variety of selected examples, we illustrate the power of molecular dynamics (MD) simulations to gain microscopic insights into systems involved in the liquid-liquid extraction of cations by macrocylic or acyclic ionophores such as calixarene derivatives, cryptands, podands. Explicit account of solvation in the source phase (water), in the receiving phase (chloroform) and at the liquid-liquid interface demonstrates the active role of solvent on the structural features of the extracted complexes and on the effect of counterions. Solvent also markedly contributes to the thermodynamics of cation complexation in homogeneous liquids and of transfer from one liquid phase to the other.