Iron-sulfur (FeS) cubane-type clusters are among the most abundant and functionally versatile metallocofactors encountered in the biosphere. Their central role stems from their unique electronic properties, characterized by an exceedingly dense manifold of low-lying excited states, as well as their rich electron-transfer (ET) chemistry. Recently, we reported the synthesis of a complete redox series of [Fe4S4(SAr)4]n‑ complexes (n=0-4),(1), demonstrating their direct relevance to biomimetic ET reactivity, particularly conformationally gated ETs.(2) This has enabled us to decipher the biophysical basis for this unique ET mechanism, ultimately being controlled by the local electrostatic environment of the cofactor. We have now expanded this approach to include H-bonding donor molecules, further underscoring the biochemical relevance of this electrostatic tuning. These insights into redox modulation and electronic structure laid the foundation for the rational design of larger iron-sulfur assemblies. Leveraging our detailed knowledge of the (electro-)chemical properties of [Fe4S4(SAr)4]n‑ complexes, we will present the stepwise construction of synthetic K-cluster mimics, which may provide a molecular-level perspective on the earliest stages of FeMo-cofactor maturation in NifB.(3) We show that transforming a [Fe4S4(SAr)4]2‑ complex into a Fe8S8 cluster with a topology relevant to both P- and M-clusters requires a sequence of 5 well-defined (electro-)chemical reactions. This synthetic route stands in contrast to previous self-assembly approaches and offers new insights into the biogenesis of some of the most structurally intricate metallocofactors known.