Single crystals of triglycine sulfate (TGS) with L-glutamine and L-methionine were grown in aqueous solutions by a slow cooling method. The grown crystals were Subjected to single crystal and powder X-ray diffraction studies to identify the morphology and the structure. FTIR and UV-visible spectra reveal the functional group identification and optical property of the grown crystals. The dielectric studies were carried out to identify the phase transition temperature and to find the dielectric constant. Microhardness studies have been carried out to assess the mechanical property. P-E hysteresis studies were carried out to find the values of spontaneous polarization and coercive field for doped TGS crystals. (C) 2008 Published by Elsevier B.V.