To meet all these requirements, we leverage a microfluidic approach that provides threedimensional (3D) control over a reaction-diffusion (RD) zone, enabling the continuous and reproducible fabrication of SCO composite fibers via the in-situ synthesis and integration of the well-known iron-triazole complex [Fe(Htrz)2(trz)](BF4) within a polymeric matrix. Taking advantage of the advanced design of the microfluidic chip, we modify different reaction parametersincluding the injection position of the chemical precursors and their relative flow rates (controlled by the flow rate ratio, FRR)to fine tune the RD zone and achieve SCO composite fibers with tailored physicochemical and magnetic properties. Moreover, we explore the potential for creating freestanding architectures and for printing complex geometries.