In conclusion, the synthesis of nine heterometallic Sn-Co/Mn nanoclusters has been achieved through a stepwise self-assem bly approach, utilizing polynuclear oxygen donors as key precur sors. Th^{e t}BuPO₃²⁻ ligands play a pivotal role in bridging trinuclear organotin clusters with Co²⁺/Mn²⁺ ions. Shielded by O/N/P-con taining ligands, the Co²⁺ and Mn²⁺ ions assume distorted tetrahe dral and hexahedral coordination environments, respectively. Lig ands featuring two or three N/P coordination sites facilitate the bridging of multiple [(ⁿBuSn)₃(MeO)₃(μ₃-O)(^tBuPO₃)₃Co] substruc tures, highlighting their structural robustness. Significantly, the dy namic magnetization measurements indicated that (Sn₃-Co₁)₂-1,5-naphyd NC exhibits a slow relaxation behavior of magnetiza tion. This study delves into the intricate self-assembly process of Sn-Co/Mn nanoclusters at the molecular level, offering valuable insights for the development of novel SMMs.