We showed that nickel Prussian blue analogue (NiPBA) films were electrochemically deposited onto a conducting transparent indium tin oxide coated with polyethylene terephthalate electrodes. The flexible NiPBA films were characterized by means of scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectronspectroscopy technique and X-ray diffraction analyses. Electrochromic performance of the flexible NiPBA films was investigated using cyclic voltammetry, chronoamperometry and chronocoulometry methods. The coloration, bleaching times and reversibility of the NiPBA film were calculated as 5.8 s, 2.7 s, and 97.37% in KCl liquid electrolyte medium, respectively. Electrocatalytic behavior of the NiPBA film towards H(2)O(2)sensor was also evaluated by chronoamperometry technique. The flexible NiPBA film showed a linear response to H(2)O(2)in concentration range of 3.92 to 15.68 mM (R-2 = 0.9906), sensitivity of 1.6272 mu AmM-1 cm(-2). After performing repeated bended cycle tests, the flexible NiPBA films showed good mechanical stability in terms of both electrochromic and H(2)O(2)sensing properties. The presented results can promote its potential application in wearable devices, displays, which are flexible states for monitoring.