In the present investigation, YxCoO:ZrO2 (x = 0.1, 0.3, 0.4) nanostructures (NS) are synthesized by co-precipitation and surface reduction methods using triethanol amine as surfactant and hydrazine hydrate as reducing agent. Triple-shaped semiconductor crystal features, morphology, optical absorptivity and chemical composition are determined by XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), UV–Vis and X-ray photoelectron spectroscopy. XRD patterns revealed mixed phase of tetragonal and cubic structure of YxCoO: ZrO2 with less impurity peaks. SEM morphology indicates nanoparticles (NPs) of YxCoO:ZrO2 spherical in nature with particle agglomerations. Average Grain size, grain boundary and interpore diameter were found to be ~ 55 nm, ~ 78 nm and ~ 115 nm, respectively. FTIR spectra of YxCoO:ZrO2 (0 ≤ x ≤ 0.4) show stretching and bending peaks at ~ 533/cm (O–Y–O bond), ~ 1024/cm (Zr–O–Zr bond), broad peak at ~ 3319/cm (Y–OH) and optical absorptivity of YxCoO:ZrO2 (0 ≤ x ≤ 0.4) with λmax spread over 286 nm to 270 nm, and absorption edges appeared in between 189 and 254 nm. Chemical compositional analysis exhibited binding energies of singlet O1s at 529.8 eV, Y 3d 5/2 and Y 3d3/2 observed at 157.8 eV and 163.9 eV, respectively, while Zr 3d5/2 and Zr 3d3/2 are observed at 180.4 eV and 182.7 eV. Photoluminescence spectrum (PL) of YxCoOZrO2 NS exhibit peaks centred around ~ 455 nm (UV region) in case of Y0.4Co0.5OZr0.1O2 NS and for Y0.3Co0.5OZr0.2O2 NS ~ 538 nm (visible region) with various Y-, O- and Co-related native defects. Emission band was observed at UV region with ~ 415 nm to ~ 480 nm broad peak (Y0.4Co0.5OZr0.1O2 NS, λexcitation = 380 nm) and ~ 502 nm to ~ 582 nm in case of Y0.3Co0.5OZr0.2O2 NS with λexcitation = 410 nm. PL emission spectra of YxCoO:ZrO2 have two emission peaks centred at ~ 455 nm and ~ 538 nm with emissions bands with blue and green wavelengths. The transitions can be ascertained with shielding of 4f shells of Y+3 ions by 6s, 5d shells by the interaction of the other Y+3 ions.