Nuclear quadrupole coupling interactions in the rotational spectrum of tryptamine

► Rotational spectra tryptamine has been observed using LA-MB-FTMW spectroscopy. ► Two Gauche-Pyrrole and two Gauche-Phenyl conformers have been detected. ► 14N quadrupole coupling constants constitute a decisive tool for this identification. ► Values of quadrupole constants have been used to identify intramolecular interactions. ► The four conformers are stabilized by a weak NH⋯π interaction.