In the present investigation, we have successfully grown optically transparent single crystals from aqueous solution by slow evaporation technique. The influence of dopant Pd 2+ on the growth process, crystalline properties of potassium acid phthalate (KAP) has been investigated. Powder XRD and ICP-OES studies confirmed the Pd 2+ ion doping into KAP crystals. The modes of vibration in the crystal lattice have been determined by FTIR analysis. Optical transmission studies were carried out by allowing the UV-NIR ray of wavelength between 190 and 1000 nm, which is to pass through the (010) face of the grown KAP crystals and the results confirm that both the pure and doped KAP single crystal shows good transparency in the entire visible region, which is suitable for optical device applications. TGA studies reveal that the purity of the sample and no decomposition is observed below the melting point. Microhardness studies reveal that the Pd 2+ doped crystals have higher hardness values than that of pristine KAP. Dielectric constant value of Pd 2+ doped KAP at 100 Hz was found to be extensively higher than that of pristine KAP. The Pd doping significantly improves the second harmonic generation (SHG) efficiency of the KAP host crystal.