Guanidine‐Based Ligands in Bioinorganic Chemistry: Coordination Modes and Applications in Anticancer Metallodrugs

Guanidine-containing molecules represent a versatile class of nitrogen-rich compounds whose unique structural and physicochemical features underpin a rich and tunable coordination chemistry. Their capacity to act as strong donor ligands, stabilize a variety of metal centers in different oxidation states, and access multiple coordination modes has established guanidine and guanidine-like cores as pivotal components in medicinal inorganic chemistry. This review provides a focused overview of metallodrugs for antitumor applications in which guanidine or guanidine-like ligands play a central role in metal coordination, highlighting how the coordination modes of the guanidine core translate into their application as anticancer metallodrugs. By correlating coordination mode, metal center, and ligand design with anticancer performance, this work underscores the potential of guanidine-based ligand platforms for the development of next-generation metal-based therapeutics.