Disclosed are star polymers comprising a polymeric body having a core with a site-isolated chromophore and a plurality of polymer chains emanating from the core; and at least one chelating moiety bonded to at least one polymer chain. Also disclosed are bimodal contrast agents derived from star polymers and further comprising at least one metal chelated by the at least one chelating moiety. Also disclosed are methods of making and using same. Also disclosed are imaging methods employing the disclosed star polymers and/or bimodal contrast agents. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.