Syntheses, structures, and magnetic properties of two hexanuclear [5×1 + 1×1] lanthanide cocrystal complexes [Ln5(L)4(LH2)2(tfa)4]·[Ln(tfa)4]·2CH3OH [Ln = Dy(1) and Tb(2)] derived from the polyhydroxy ligand 2‐(hydroxymethyl)‐6‐carbaldehyde‐4‐methylphenol (LH2) are reported. Compounds 1 and 2 crystallize in the triclinic system with space group P1. X‐ray crystallography reveals that 1 and 2 are cocrystals comprising one cationic pentanuclear [Ln5(L)4(LH2)2(tfa)4]+ unit and one anionic mononuclear [Ln(tfa)4]–unit as well as two molecules of methanol as solvent of crystallization. Both complexes form a [2.2] spirocyclic topology fashioned core due to merging of two triangular geometries composed of Ln(III) ions through a common vertex. The central Ln(III) ion in the spirocyclic pentanuclear assembly is eight‐coordinate with distorted square antiprism geometry. On the other hand, the peripheral eight‐coordinate Ln(III) ions are in a distorted trigonal dodecahedron geometry. The comprehensive magnetic study reveals that compound 1 displays slow relaxation of magnetism.