Ca2+ substituted La2CuO4 (LCC) perovskite nanostructures have been prepared by microwave combustion. X-ray diffraction analysis indicates that the undoped La2CuO4 (LCC0) crystallizes within a single perovskite-type phase with an orthorhombic crystal structure. For smaller Ca2+ doping of 0.1 (LCC1), a minor impurity was observed, while for concentrations 0.2 (LCC2) and 0.3 (LCC3), orthorhombic-to-tetragonal phase transformation occurs. In contrast, the tetragonal phase disappears at 0.4 and 0.5 (LCC4 and LCC5) as confirmed by XRD and Rietveld refinements. The orthorhombic and tetragonal perovskite phases have an average crystallite size in range 34.2–54.3 nm and 39.8–39.4 nm, respectively. Fourier transform infrared spectroscopy study established the characteristic absorption bands of La2CuO4 perovskite orthorhombic structure; the correlated bands are observed at 683 cm−1 for La-O and 516 cm−1 for Cu-O stretching modes. The optical band gap as determined by diffuse reflectance spectroscopy (DRS) increases then decreases with increasing Ca2+ content due to the quantum confinement effect. The surface morphology observations using scanning electron microscopy display nano-sized pores and pore walls are fused grain boundaries. Magnetization-field curves exhibit a ferro-/paramagnetic behavior for undoped La2CuO4 while Ca-doped system has only a paramagnetic behavior due to the exchange of A and B sites within La2CuO4 host lattice. © 2019 Elsevier Ltd