Single crystals of pure, Cu2+ and Mg2+ doped L-arginine acetate (LAA) were grown successfully by slow evaporation technique. In order to improve the device characteristics of LAA crystals, metal dopants of Cu2+ and Mg2+ were incorporated into the parent crystals. The grown pure and doped crystals were confirmed by X-ray powder diffraction studies. The pure and doped crystals were characterized by Fourier transform Raman (FT-Raman) and thermal studies. Absorptions of these grown crystals were analysed using UV-Vis-NIR studies, and it was found that these crystals possess minimum absorption in the entire visible region. Nonlinear optical studies of pure and doped crystals were carried out and it reveals that the dopants have increased the efficiency of LAA crystals.