A new [P2V3W15O62]9 - cluster based covalent polyoxometalate-organic hybrid (P1) containing a naphthol-amide-Tris derivative has been synthesized and characterized using standard analytical and spectroscopic techniques including single crystal X-ray diffraction analyses. P1 exhibits interesting self-assembly behaviour leading to the generation of sim;200 nm spherical aggregates in solutions as revealed by DLS and TEM analyses. Standard in vitro experiments revealed that P1 is capable of exhibiting moderate antioxidant properties under standard experimental conditions. © 2015 Elsevier B.V. All rights reserved.