Synthesis of core-shell nanoparticles consisting of a Fe3O4 magnetic core, which are covered by a zirconia shell (Fe3O4@ZrO2), is presented. Sulfonic acid groups are conveniently loaded on as-prepared Fe3O4@ZrO2 core-shell magnetic nanoparticles support in which chlorosulfonic acid is used as a sulfonating agent. The resulting nanocatalyst was well characterized through XRD, FT-IR, TGA, FE-SEM, TEM, EDX, VSM, and pH analyses. Catalytic activity of the synthesized nanoparticles has been investigated for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and 1-amidoalkyl-2-naphthols.