<p>This research focuses on developing dielectric materials through the incorporation of metal complexes of benzoxazine and transition metals as fillers in commercial resins, utilizing a 3D printing process known as stereolithography. The benzoxazine monomer based bisphenol A, (6,6-(propane-2,2-diyl)bis(3-cyclohexyl-3,4-dihydro-2H-benzoxazine) (BM), was synthesized via a Mannich reaction using paraformaldehyde, cyclohexylamine, and bisphenol A in a 4:2:1 molar ratio. The synthesized BM was subsequently reacted with cobalt(II) chloride to form the BM-CoCl₂. The successful formation of the BM complex was confirmed through UV–Vis, and it was found that BM and cobalt formed a coordination complex in a 4:1 molar ratio, as confirmed by TGA techniques. BM-CoCl₂ was incorporated into a commercial resin and processed via SLA to fabricate samples for evaluating both dielectric and mechanical performance. Adding 1 part per hundred of resin (phr) of BM-CoCl₂ led to a dielectric constant 2.4 times higher than that of both the commercial resin and the Resin/BM composite. As the concentration of BM-CoCl₂ increased to 5, 10, and 15 phr, the dielectric constant continued to rise, while the loss tangent values remained very low. Furthermore, the inclusion of BM-CoCl₂ as an additive enhanced the elongation of the resin, broadening its potential for a broader range of industrial applications. Additionally, at the end of its service life, the Co₃O₄ residue generated through the incineration of the material can be repurposed as a catalyst.</p>