AbstractThe investigation seeks to develop gold‐shelled carbon‐coated manganese ferrite nanodots enclosed within oxidized alginate polymeric hydrogels (MNF@C‐Au@OSA) to improve encapsulation efficiency, biocompatibility, and multimodal imaging capabilities. These engineered particles, MNF@C‐Au@OSA, are crafted through a hydrothermal synthesis, succeeded by the application of gold nanoparticle shelling and subsequent encapsulation within hydrogels derived from synthesized alginate derivatives, enhancing their overall appeal. Diverse characterization methodologies are employed in order to validate the multiple steps of the synthesis process. The resulting engineered nanoparticles exhibit dual‐mode (T1 and T2) magnetic resonance imaging (MRI) contrast capabilities and compatibility with computed tomography (CT) and fluorescence‐based imaging. To illustrate minimal toxicity, A375 cell lines are utilized for in vitro testing, whereas zebrafish embryos are employed for in vivo assessments. A Chorioallantoic Membrane Model (CAM) is used to establish the antiangiogenic characteristics of MNF@C‐Au@OSA, which is confirmed by histopathological observations. Taking these studies together, one can conclude that the engineered MNF@C‐Au@OSA possesses multimodal imaging capabilities and has demonstrated antiangiogenic properties, thereby establishing them as potential theranostic agents.