Dielectric, thermal, and mechanical behavior of an efficient nonlinear crystal, nickel boro phthalate (NBP), grown by a slow evaporation solution growth technique, is characterized for optoelectronic applications. Ultraviolet absorption study identifies the lower cutoff wavelength as 281 nm. This low value along with transparency in the visible and infrared regions establishes that NBP is a probable nonlinear material. The frequency and the temperature dependency of dielectric constant and dielectric loss are probed. AC conductivity and activation energy are computed, to examine the semiconducting ability of the crystal. Thermal gravimetric analysis and differential thermal analysis are carried out to determine the decomposition temperature. Mechanical characterization is performed by the Vickers microhardness test. The study reveals that NBP comes under the category of soft material. Mechanical properties such as the elastic stiffness constant, brittleness index, yield strength, and fracture toughness are explored.