We have shown that as the [Dy(Cp ttt )(Cp*)] + cation is of intermediate steric bulk, it can form both separated ion-pair and contact ion-pair polymorphs with a weakly coordinating perfluoroalkoxyaluminate anion in the solid state. The separated ion-pair polymorph exhibits magnetic behavior that is in accord with previously reported isolated dysprosocenium SMMs, whilst the weak equatorial interaction in the contact ion-pair is shown to diminish magnetic properties. Surprisingly, the Orbach relaxation rate does not appear to be significantly affected, as the axiality of the crystal field is not substantially reduced in the contact ion-pair polymorph.