Nanobrick-like WO₃ thin films have been synthesized via facile hydrothermal route. Nanostructured WO₃ thin films were characterized using X-ray diffraction (XRD), UV–Vis–NIR spectrophotometer, scanning electron microscopy (SEM), atomic force microscopy (AFM) to investigate the intentional properties such as phase structure, optical properties and surface morphology. Moreover electrochromic (EC) performance of WO₃ thin film was investigated in 0.5 M LiClO₄/PC by means of cyclic voltammetry (CV), chronocoulometry (CC) and chronoamperometry (CA). The value of diffusion coefficient (D) was determined from anodic peak current and was found to be 1.51 x 10^-9 cm²/s. The response time of 6.9 s for bleaching (t_b) and 9.7 s for coloration (t_c) was observed with excellent reversibility 76%. The coloration efficiency for nanobricks WO₃ is 39.24 cm²/C. CIE 1931 L*ab values for colored and bleached films were estimated at 2° observer using D-65 illumination. The electrochromic studies show highly reversible and the stable nature of WO₃ thin film which provides a versatile and promising application towards the fabrication of smart windows.