Three new heterobimetallic Schiff base complexes of formula [(LZnCl)2Gd(H2O)](ZnCl4)0.5 (2), [(LZn(OH))(LZnCl)Sm(H2O)](ZnCl4)0.5 (3) and [(LZnCl0.5(OH)0.5)(LZnCl)Dy(H2O)](ZnCl4)0.5 (4) were designed from the reaction of the metallo-ligand ZnL (1) (H2L=N, N′-bis(3-methoxysalicylaldiimine)-1,3-propylene-2-ol) and lanthanide salt in a ratio 1 to 1. The crystallographic structures of 2–4 were resolved by single crystal X-ray diffraction. Light irradiation allowed the observation of a broad emission centered on the organic ligand which is exalted upon Zn(II) coordination. 1 is able to act as a metallo-organic chromophore for the sensitization of the Sm(III) luminescence. Finally the Dy(III) derivative displayed Single-Molecule Magnet (SMM) behavior with an opening of the hysteresis loop up to 5 K and a magnetic relaxation operating through Orbach, Raman and Quantum Tunneling of the Magnetization (QTM) at 0 Oe while under an applied magnetic field the QTM is efficiently cancelled. © 2022 Wiley-VCH GmbH.