The production of materials that contain more than one functional constituent, the so-calledmultifunctional materials, is quite relevant in advanced technology. By acting as building blocks,nanoparticles can be suitably explored for generating higher-order multifunctional structures. In thisregard, herein, a special clustered magneto-fluorescent superstructure has been developed for nondestructivedetection of flaws and shallow subsurface discontinuities in industrial ferromagneticmaterials. The strategy consists of the solvophobic-controlled assembly of organic-based maghemitecores and water-based II–VI quantum dots, in the presence of hexadecyltrimethyl-ammonium bromide,CTAB, as a compatibilizer agent. This composite exhibited a high magnetic response (smax ¼ 66 emug1) and uniform size, in addition to tunable optical properties (QY ¼ 78%). The strategy of utilizingnanoparticles as magneto-fluorescent nanoprobes to identify tiny slits represents a great advance, forimproving the capability of precisely revealing the fracture boundary locations by visual real-timeinspection. The nanoscale probes exhibit a low signal-to-noise ratio and a higher competitiveperformance in relation to the existing micrometric detection systems. © The Royal Society of Chemistry 2021.