The growing popularity of lanthanides in molecular magnetism has given rise to new difficulties that must be overcome for the successful determination of the relevant physical quantities necessary to describe single-molecule magnet (SMM) behaviour. For transition metal compounds, the magnetization (typically experimentally obtained as a function of temperature and magnetic field) facilitates the estimation of chemically intuitive parameters, for example, magnetic super-exchange coupling constants and magnetic anisotropy parameters. The easy availability of this information has led to several studies of correlations between chemical structures and magnetic properties. In turn, this work initiated fundamental research in tuning, for instance, 3d metal ion-based SMMs. For lanthanide ions, a similar interest surely exists, but several problems arise before a similar level of knowledge can be achieved. First of all, the intrinsic lability of lanthanide ions, combined with the lack of preference for specific coordination geometry and hence the difficulty of accurately predicting coordination geometry, creates a major obstacle for controlling and tuning the synthesis of 4f SMMs [1]. ...