ABSTRACT In this work, first, VO-acetylacetonate coordination system with 2-(pyridin-4-ylmethylene) hydrazine-1-carbothioamide (VO(acac)2L) was synthesised via sonochemical routes. Then POAP/VO(acac)2L films were fabricated through electropolymerization of poly ortho aminophenol (POAP) in the presence of VO(acac)2L and used as the active electrode of an electrochemical supercapacitor (SC) with a significant electrochemical properties improvement. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) was applied to characterise the structural state of the prepared samples. Also, some electrochemical methods such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) were carried out for the system performance investigation. This work may open an avenue to develop efficient and robust nanocomposite materials for an energy storage device in an acidic medium.