A transparent optically good quality dipotassium tetra borate monohydrate single crystal of 9 mm x 8 mm x 8 mm was successfully grown by slow evaporation technique. S-XRD study revealed that the crystal belongs to the triclinic crystal system with P1¯ space group. The vibration levels of the functional groups present in the DKTBMH compound were determined using FT-IR and FT-Raman spectral analyses. The UV–Vis-NIR spectrum confirms that the grown crystal may be well constructive material for optical windows application. The lower cut-off wavelength of the crystal was found to be 231 nm. The DKTBMH crystal was thermally stable upto 150 °C. The specific heat capacity of DKTBMH crystal was measured. The laser damage threshold value for DKTBMH was measured to be 8.6 GW/cm² at 1064 nm. The mechanical studies confirmed that DKTBMH crystal belongs to the soft material category. The negative photoconductivity of DKTBMH crystal is confirmed by photoconductivity studies. Third-order susceptibility, second-order hyperpolarizability, and FOM were determined from Z-scan measurements. The observed results confirm that DKTBMH crystal exhibits self-defocusing nature and two-photonn absorption.