A 1:1 molecular complex of benzotriazole p-hydroxybenzoic acid (BPHB) single crystal was grown by slow evaporation solution growth method at ambient temperature. The formation of title compound was confirmed through single-crystal X-ray diffraction analysis and it is found that the compound crystallises in orthorhombic system with Pna21 space group. The modern spectroscopic studies such as Fourier transform infrared, FT-NMR and UV–vis–NIR characteristics were carried out to reveal the molecular structure and optical window of the compound. TG/DTA analysis was performed and found that the compound is stable up to 170.8 °C. The mechanical strength of the BPHB was examined using Vicker’s microhardness tester. Kurtz and Perry powder technique was used to assess the second harmonic generation of the grown crystal and its efficiency it is found to be 1.02 times greater than that of potassium dihydrogen orthophosphate. Antimicrobial and anticancer evaluations were made on the title compound using novel resazurin reduction assay and MTT assay methods which results superior biological activities comparable to available drug products.