Single crystals of Potassium pentaborate were grown by the slow evaporation method at room temperature. Single crystal XRD provided evidence that the crystallized material was Potassium pentaborate and the lattice parameter was also ascertained. Solubility of the material was determined gravimetrically. The stability of the material was studied by observing the metastable zone width using the polythermal method. The induction period was determined at different temperatures by varying the supersaturation from 1.1 to 1.5. Various nucleation parameters such as interfacial energy, Gibbs volume free energy change, critical volume free energy change, radius of critical nuclei and nucleation rate were estimated. Optical studies were carried out in the region of 200-800 nm, it was inferred that the material possessed a wide transparency in visible region with the cutoff wavelength 243 nm. NLO property of the material was confirmed by Q-switched Nd-YAG technique. © 2013 Elsevier B.V.