Purging of heavy metals like chromium and manganese from water using various adsorbents is the need of the hour for our environment. Copper iodide nanoparticle (CuI NP) has garnered a lot of attention due to its singular physical and chemical properties. The present study reports the of use of green synthesized CuI NP using Hibiscus rosa-sinensis L. flower extract which contains the anthocyanin, cyanidin-3-sophoroside (acts as both reducing and capping agents) in the removal of aqueous Cr(VI) and Mn(VII) ions. The synthesized CuI NP was characterized and was found to be nanocrystalline in nature, showing the presence of some surface crystal defects and having a high surface area making it a good adsorbent with adsorption capacities of 169.5 mg/g for Cr(VI) and 200 mg/g for Mn(VII) ions. The kinetics of metal removal was probed. The removal of metals was also probed using Freundlich and Langmuir adsorption models.