The SANS4NCC project aims at understanding, under operating conditions, the fundamental mesoscale interactions in magnetoelectric nanocomposites by employing state-of-the-art static and time-resolved neutron-scattering techniques. The microstructure of the materials of interest consists of embedded 10-100 nm magnetostrictive nanoparticles [CoFe2O4 or Galfenol (FeGa)] in a nonmagnetic lead-free ferroelectric [(BaxCa1-x)(ZryTi1-y)O3 (BCZT)] or piezoelectric (ScAlN) matrix. In order to investigate their magnetic and electric functionalities in response to an externally applied magnetic field (both DC and AC), the technique of small-angle neutron scattering (SANS) will be implemented to assess the spin and strain distributions inside the volume of the material, on the relevant mesoscopic length scale (about 1-300 nm), and with a 10 microsecond time resolution. Embedded magnetostrictive nanoparticles will enable a strain-mediated sensitivity of the ferroelectric/piezoelectric matrix to applied magnetic AC and DC fields. Static and time-resolved SANS will provide important information about the magnetostrictive-ferroelectric and magnetostrictive-piezoelectric nanoparticle-matrix interactions on a scale of a few nanometres including the interfacial regions. SANS4NCC will contribute to (i) the advancement of our fundamental understanding of magnetic SANS on magnetic nanoparticles in general and on magnetoelectric nanocomposites in particular, and to (ii) optimizing the chemical vapor deposition process, which is a dry synthesis route for the deposition of relevant magnetostrictive, ferroelectric, and piezoelectric materials and their sequential growth into magnetic nanocomposites with controlled texture, architecture, and interface quality. We believe that the results of the SANS4NCC project will turn magnetic SANS into a powerful and unique operando analysis technique for studying magnetoelectric coupling.