Potassium Hydrogen Oxalate Dihydrate (PHODH) is a semi-organic nonlinear optical (NLO) material. They are synthesized by chemical method. Crystals of PHODH are successfully grown by slow evaporation solution growth technique using deionized water as a solvent. The grown crystals are analyzed by Single crystal XRD, FT-IR, UV-Vis, TG/DTA, Vicker’s micro hardness test and NLO studies. The structure of PHODH as obtained from the XRD analysis is triclinic with space group P1.The single crystal XRD analysis reveals the extended framework architecture of PHODH through self-assembly process, involving short range and directional bonds among many other different interactions. Fourier Transform Infrared analysis has confirmed the various functional groups present in the grown crystals. PHODH crystals are optically transparent in the UV-Visible region and a maximum transparency of 80% is witnessed. The UV cut-off wavelength of PHODH is found to be 256nm. The thermal studies reveal that PHODH is stable up to 288˚C.
