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A fine\u2010tuning of the properties of redox\u2010active ligands focusses on the redox potential and frontier orbital energies, as well as the steric demand and coordination mode. In this work, we report the first synthesis of new\n                    <jats:italic>o<\/jats:italic>\n                    \u2010diguanidino\u2010benzene ligands in which the two guanidino groups are connected through an alkyl chain of different length. The introduction of an ethylene bridge between the two guanidino groups turns a strongly coordinating ligand into a noncoordinating molecule, while keeping its strong Br\u00f8nsted basicity. These features qualify the ethylene\u2010bridged compound as a powerful alternative to Huenig's base, diisopropyl\u2010ethyl\u2010amine. The change from an ethylene to a propylene bridge switches back on the coordination ability. It is also possible to introduce a methyl group to the central C atom of the propylene bridge without loss of nucleophilic properties. The analysis, based on a variety of metal complexes, identifies three structural parameters to assay the structural restraint. Macrocyclic tetraguanidines are also formed.\n                  <\/jats:p>","DOI":"10.1002\/chem.202502457","type":"journal-article","created":{"date-parts":[[2025,10,25]],"date-time":"2025-10-25T10:23:08Z","timestamp":1761387788000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Steric Restraints in Redox\u2010Active Guanidine Ligands and Their Impact on Coordination Chemistry"],"prefix":"10.1002","volume":"31","author":[{"given":"Eliane","family":"Engels","sequence":"first","affiliation":[{"name":"Ruprecht\u2010Karls\u2010Universit\u00e4t Heidelberg: Universit\u00e4t Heidelberg Institut f\u00fcr Anorganische Chemie Heidelberg 69120 Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hanna","family":"Koepcke","sequence":"additional","affiliation":[{"name":"Ruprecht\u2010Karls\u2010Universit\u00e4t Heidelberg: Universit\u00e4t Heidelberg Institut f\u00fcr Anorganische Chemie Heidelberg 69120 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