A novel Deep Eutectic Solvent (DES) can be formed between glycerol (Gly) and potassium iodide (KI). This study presents a comprehensive physicochemical characterization of these designed DES. The DES compositions, DES-Gly-KI and DES-Gly-KI-EtOH, consist of a hydrogen bond donor (Gly), a hydrogen bond acceptor (KI), and a viscosity-reducing solvent (ethanol (EtOH)). Experimental methodologies, including UV–VIS spectroscopy, mass spectrometry, Fourier transform infrared spectroscopy, and rheological studies such as density and viscosity, are employed to elucidate molecular interactions and structural characteristics. Karl Fischer titration is also conducted to analyze the moisture content in this prepared DES systems. The electrochemical performance of supercapacitors is also analyzed using cyclic voltammetry and electrochemical impedance spectroscopy. The specific capacitance values are found to be 10.32 F/g and 19.18 F/g for DES-Gly-KI and DES-Gly-KI-EtOH-5, respectively. The findings contribute in understanding DES behaviour, reveal distinctive physicochemical attributes, offering valuable insights into crafting and optimizing novel DESs, which is customized to meet distinct industrial requirements.