Single molecule magnets (SMMs) have potential in high-density data storage, quantum information technology and spintronics. Currently, the advancement of SMMs is typically based on maximizing the two key experimental parameters: the effective energy barrier (Ueff) to magnetic reversal and the blocking temperature (TB) below which magnetic hysteresis can be observed. Due to the large magnetic anisotropy, lanthanide-based SMMs stand out as promising candidates to drive ground breaking advances in molecular magnetic performance. Historically, the first lanthanide SMMs [Ln(Pc)2] -(Ln = Tb, Dy, Pc = dianion of phthalocyanine) with Ueff values of 330.9 K (Tb) and 40.3 K (Dy) were introduced by Ishikawa and coworkers in 2003, which were later integrated into devices to be read out at the single-molecule level implementing quantum algorithms into a SMM. In 2011, the first organometallic lanthanide SMM [(C5Me5)Er(Cot)] was reported by Gao and exhibits an Ueff of 323 K. The enhancement of the magnetic properties of lanthanide SMMs is closely related to their molecular architectures. For Dy and Tb 3+ with oblate-spheroidal electron densities, axial ligand fields are predicted to enhance the Ueff values. Following this design strategy, the enormous potential of dysprosium complexes in this regard has been discovered recently. The magnetic anisotropy of the oblate Dy 3+ ion can be strongly enhanced by being sandwiched between two bulky cyclopentadienides (Cp R = C5R5) derivatives, enforcing a highly axial ligand field. A family of dysprosocenium sandwich-type cations [Dy(Cp R )2] + with magnetic hysteresis at up to liquid nitrogen temperature have been disclosed. The pioneering example is [Dy(Cp ttt )2] + (Cp ttt = C5H2tBu3-1,2,4) reported in 2017 which exhibits magnetic hysteresis at 60 K, while for [Dy(Cp iPr5 )(Cp*)] + (Cp iPr5 = C5iPr5, Cp* = C5Me5) hysteresis was observed at the current record temperature of 80 K. Comparably, the bis-Cp ttt Tb species [Tb(Cp ttt )2] + was disclosed in 2018, however, with magnetic hystereses at much lower temperatures compared to the Dy analogs.