<p>Zinc oxide nanoparticles exhibit distinctive optical, biological, electrical, and catalytic properties that render them extremely promising for an extensive array of applications. For this study, zinc complexes were thermally broken down to synthesis zinc oxide nanoparticles. Complexes were prepared by condensation reaction of N, N′′′Z)-N′,N′′′-(1,2-diphenylethane-1,2-diylidene)di(nicotinohydrazide (BNH) and various zinc salts. Fourier transform infrared spectroscopy, UV–visible, mass spectra, and thermogravimetric analysis were used to characterise zinc complexes. Several analytical techniques were used to characterise the nanoparticles, including X-ray diffraction analysis and electron microscopy including scanning and transmission techniques. Results showed that crystalline zinc oxide nanoparticles with distinct morphologies and nanoscale dimensions were formed. Methylene blue and methyl orange were used to test the potential of zinc oxide nanoparticles as a photocatalyst, and the results were promising. In vitro antidiabetic, in vitro antioxidant, sun protection factor, and in vitro scratch wound healing experiments demonstrated the advantages of zinc oxide nanoparticles.</p> Graphical abstract <p></p>