The Schiff-base (2-aminoethyl)hydroxybenzoic acid (H2L) as a proligand was prepared in situ from 3-formylsalicylic acid and ethanolamine (ETA). The mononuclear {[Y(HL)4][ETAH] center dot H2O} (1) and {[Dy(HL)4] [ETAH] center dot 3MeOH center dot H2O} (2) and tetranuclear {[Y-4(HL)(2)(L)(4)(mu(3)-OH)(2)] center dot 4MeOH center dot 4H(2)O} (3), {[Dy-4(HL)(2)(L)(4)(mu(3)-OH)(2)]center dot 5(MeOH)(2) center dot 7H(2)O (4), and {[Dy-4(HL)(8)(L)(2)]center dot 4MeOH center dot 2H(2)O}(5) rare-earth metal complexes of this ligand could be obtained as single-crystalline materials by the treatment of H2L in the presence of the metal salts [Ln(NO3)(3) center dot(H2O)(m)] (Ln = Y, Dy). In the solid state, the tetranuclear compounds 3 and 4 exhibit butterfly structures, whereas 5 adopts a rectangular arrangement. Electrospray ionization mass spectrometry data of the ionic compounds 1 and 2 support single-crystal X-ray analysis. The yttrium compounds 1 and 3 show fluorescence with 11.5% and 13% quantum yield, respectively, whereas the quantum yield of the dysprosium complex 4 is low. Magnetic studies on the dysprosium compounds 4 and 5 suggest the presence of weak antiferromagnetic interactions between neighboring metal centers. Compound 4 shows single-molecule-magnet behavior with two relaxation processes, one with the effective energy barrier U-eff = 84 K and the preexponential factor tau(0) = 5.1 x 10(-9) s.