The molecular design of smart polymer surfaces and control over functionality in a way that the properties can be changed by external triggers garnered a great deal of attention of polymer chemists in the last decade. Here, we introduce the formation of a dual-responsive, i.e. reduction- and oxidation responsive, cobalt-containing polymer core-shell particle system, displaying a reversibly switchable behavior by means of chemical oxidation reagents as well as electrochemistry experiments. The responsiveness is based on a cobalt(I)-containing shell material, which is obtained by a surface-initiated atom transfer radical polymerization (SI-ATRP) protocol for (eta(5)-cyclopentadieny1-4-hydroxybutan-1-on) cobalt(eta(4)-tetraphenyl-cyclobutadiene) methacrylate (CpCoCbMA). The novel metallopolymer particles featuring a cobalt-containing shell are investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), while control over the ATRP approach is shown by characterizing freely formed poly(CpCoCbMA) chains by size-exclusion chromatography (SEC). The responsive behavior of the poly(CpCoCbMA)-containing shell is investigated by dynamic light scattering (DLS) and cyclic voltammetry (CV) measurements indicating a tremendous change of the particle hydrodynamic radii and dispersion capability in organic polar and non-polar solvents. Transformation of these preceramic cobalt-grafted core-shell particles to cobalt oxide-based materials is investigated after convenient thermal treatment. Overall, the herein reported redox-mediated core-shell cobalt-containing polymer architectures open a variety of applications for switch able and electrochemical devices. (C) 2017 Elsevier Ltd. All rights reserved.