In the present work, novel core-shell polymer magnetic colloids are prepared and employed as a potential candidate in ultrasensitive molecular imaging. The synthesized colloids possess high colloidal stability, magnetization (43.85 emu g-1) and uniformity of particle size with an average diameter of 527 nm. FTIR spectrum of magnetic emulsion shows two characteristic peaks at 570 and 630 cm-1 which related to Fe-O vibration bands. Both T1 and T2 relaxation times were successfully measured. Based on signal intensities, the prepared colloids observed to perform as better T2 weighted contrast agents. The T2-weighted MR images showed significant signal intensity reduction and contrast darkening. Moreover, the prepared colloids were also employed to fabricate thin films via a facile method of layer by layer self-assembled multilayers (LBL-SAMU) to explore their potential application in imaging. Uniform particle size distribution with spherical morphologies was obtained for the fabricated bilayers. In addition, a 20% increment in iron contents was observed for 5-15 bilayer thin films decorated with film colloidal particles. The reported work opens new avenues for designing powerful T2 contrast agents in various biomedical applications such as analysis of biomacromolecules, diagnostics, and therapy.