Later, in 2020, Real and co-workers also explored the extrinsic and intrinsic nature of luminescence in correlation with SCO properties in a series of 3D Fe(II) Hofmann-type CPs . Similarly, crystals of 36@pyr and 37@pyr were obtained following a similar protocol with methanol solutions of fluorophoric pyrene moiety, L26 instead of L25. Crystallographic analyses revealed that the structure of all 3D CPs was essentially similar to that of 32@pyr. However, the most notable changes were observed in the accessibility of the pcu framework depending on the length of the bridging ligands. Moreover, strong - stacking among guest pyrene molecules and the coordinated bridging ligands were observed for the guestinserted CPs 36@pyr and 37@pyr . In contrast, a symmetry breaking with the change of the space group from monoclinic P2/c to orthorhombic Cmma upon decreasing temperature from 280 to 100 K was observed in 35 (Fig. ). Similar to 32@pyr, the change in average Fe-N bond distance of around 0.2 Å between 100 K and 280 K, confirming SCO in the system. Magnetic properties of all the Fe(II) CPs 34, 35, 36@pyr, and 37@pyr were investigated by magnetic susceptibility measurements between 300 and 50 K (Fig. ). For all CPs, the observed T value at 300 K is around 3.20 cm 3 mol -1 K, confirming the HS state of Fe(II) center with significant orbital contributions. Upon lowering the temperature, T vs T plot for CP