Coordination polymer (CP) core-shell nanoparticles with Gd-based CP (GdCP) as core and Eu-based CP (EuCP) as shell have been successfully prepared. Allantoin was employed as the organic building block without the assistance of any template. The composition, size and structure of the core-shell nanospheres were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TG). Results show that the resultant cores are uniform nanospheres with diameter of approximately 45 nm, while the diameters of the core-shell nanospheres are increased to approximately 60 nm. The core-shell products show enhanced luminescence efficiency than the core under 980 nm laser excitation and decreased down-conversion luminescence when excited at 394 nm. (C) 2016 Elsevier Inc. All rights reserved.