Magnesium chloride doped L-Threonine dihydrogen phosphate crystals have been successfully grown by slow evaporation method. X-ray diffraction studies were used to determine the cell parameters. The structural and optical properties of the grown crystals were analyzed by FT-IR and UV-vis-NIR spectral studies. Photoconductivity and dielectric studies were carried out to understand the response of the material to the incident radiation and dielectric behavior of the material. FESEM - EDAX and ICP-OES studies confirm the presence of phosphorous and magnesium in the crystal. The second harmonic generation (SHG) behavior of the grown crystal was confirmed by Kurtz-Perry powder technique.