Magnetic nanocrescent Raman probes (see Figure) can not only serve as stand-alone surface-enhanced Raman scattering (SERS) substrates with high local electromagnetic-field enhancement factors, but can also be controlled by external magnetic fields to produce translational and rotational motion of the nanoprobes. Their near-IR optical activities may be useful for biomedical imaging, as near-IR radiation results in deeper tissue penetration and minimal photothermal damage.