Electronic and IR transitions of neurotransmitters, such as catecholamines and their derivatives have been measured by the supersonic jet laser spectroscopy combined with laser desorption technique.  The number of stable conformers in the gas phase was determined by UV-UV hole-burning spectroscopy.  The conformations of stable conformers were analyzed by the combination of the IR dip spectroscopy and quantum chemical calculations.  The relation between aromatic ring and conformation will be discussed