Presented mannan-based polymers have promising properties for tumor and metastasis imaging due to their biocompatibility, nanosize and specificity for the immune cells. In this study, two mannan-based polymers were tested by multimodal imaging (MRI and fluorescence). The polymers showed superior imaging properties compared to a commercially available contrast agent. FLI signal at the liver and higher signal at the injection site in the mouse with MN-Ox suggested slower elimination process due to addition of polyoxazoline chains in its structure. Both probes were visualized by MR and optical imaging modality at the injection sites and in the lymph nodes of the experimental mice suggesting their promising properties for cancer diagnosis.