This development of MRI-visual order-disorder structures for cancer nanomedicine explores pH-trigger mechanism for theragnosis of tumour hallmark functions. Superparamagnetic iron oxide nanoparticles (SPIONs) stabilised with amphiphilic poly(styrene)-b-poly(acrylic acid)-doxorubicin with folic acid (FA) surfacing is employed as a multi-functional approach to specifically target, diagnose and deliver drugs via a single nanoscopic platform for cancer therapy. The functional aspects of the micellar nanocomposite is investigated in vitro using human breast SkBr3 and colon cancer HCT116 cell lines for the delivery, release, localisation and anticancer activity of the drug. Our work shows, for the first time, concentration dependent T 2 -weighted MRI contrast for a monolayer of clustered cancer cells. The pH tunable order-disorder transition of the core-shell structure induces the relative changes in MRI contrast. The outcomes elucidate the potential of this material for smart cancer theranostics by delivering non-invasive real-time diagnosis, targeted therapy and monitoring the course and response of the action before, during and after the treatment regimen.Submitted to 3