We will study the bottom-up approach to molecular recognition in biological systems with a particular emphasis on neurotransmitters aiming at ultimately understanding their function at physiological conditions. We will reply on a combined experimental (Infrared spectroscopic) and theoretical (electronic structure calculations, interaction potential development and refinement, molecular dynamics simulations) approach. Especially, we will focus on identifying the conformers of neutral and protonated forms of adrenaline, noradrenaline, serotonin, nicotine and nornicotine in the gas phase and hydrated clusters as well as their conformational dependence on the environment under near physiological conditions.