The synthesis, structures, and magnetic properties of two heterometallic (CuII-DyIII) clusters are reported. The first structural motif displays a pentanuclear (Cu4DyIII)-Dy-II core, while the second one reveals a nonanuclear (Cu6Dy3III)-Dy-II core. We employed delta-vanillin-based Schiff base ligands combining delta-vanillin with 3-amino-1-propanol, H(2)vap, (2-[(3-hydroxy-propylimino)-methyl]-6-methoxy-phenol), and 2-aminoethanol, H(2)vae, (2-[(3-hydroxy-ethylimino)-methyl]-6-methoxy-phenol). The differing nuclearities of the two clusters stem from the choice of imino alcohol arm in the Schiff bases, H(2)vap and H(2)vae. This work is aimed at broadening the diversity of (CuDyIII)-Dy-II clusters and to perceive the consequence of changing the length of the alcohol arm on the nuclearity of the cluster, providing valuable insight into promising future synthetic directions. The underlying topological entity of the pentanuclear Cu4Dy cluster is reported for the first time. The investigation of magnetic behaviors of 1 and 2 below 2 K reveals slow magnetic relaxation with a significant influence coming from the variation of the alcohol arm affecting the nature of magnetic interactions.