The synthesis of a novel spermidine-based tricatecholate compound and the corresponding carbacephalosporin conjugate are described. Interestingly, both compounds exhibited significant siderophore (growth-promoting) activity for several strains of E. coli. We have recently reported the synthesis and antimicrobial activity of a spermidine-based catechol siderophore-carbacephalosporin conjugate (3). The design of conjugate 3 was derived from the previous synthesis of spermexatol [2] (1), a new type of spermidine-based siderophore. Spermexatol [2], which contains both hydroxamate and catechol ligands, closely resembles the natural spermidine-containing iron chelators, parabactin (4) and agrobactin (5). Spermexatol [2] was shown to substitute for natural siderophores in mutant strains of E. coli and Vibrio cholerae. Attachment of a β-lactam antibiotic to the spermexatol nucleus, as shown with conjugate 3, resulted in the inhibition of microbial growth. This type of iron transport-mediated drug delivery has shown promise with catechol conjugate 3 as well as other catechol and hydroxamate siderophore-based β-lactam conjugates. In the initial design of conjugate 3, the antibiotic component was attached to the central portion of the spermidine base by a succinic acid spacer. Thus, this conjugate formally contained only two bidentate ligands and its ability to complex and chelate iron with 1:1 stoichiometry was uncertain. Although natural examples of quadradentate iron chelators containing both hydroxamate (rhodotorulic acid) and catechol ligands (bis(2,3-dihydroxybenzoyl)-L-lysine) exist, we wished to study the effect of providing an additional bidentate ligand to provide a hexacoordinate molecule capable of forming a more common 1:1 complex with ferric ion. The best example of a tricatecholate siderophore is enterobactin (6). The iron binding and growth promoting abilities of enterobactin have been investigated extensively. Many synthetic enterobactin analogs have been produced, including carbocyclic analogs (e.g., MECAM) and a lysine-based dipeptide analog. Linear and cyclic spermidine-based tricatechol derivatives also have been reported, but no indication of their growth promoting ability was given. Furthermore, in the earlier reported tricatecholate spermidine compounds, no functionality suitable for attachment of an antibiotic was included. In this communication, we report the synthesis of a novel spermidine-based tricatechol iron chelator (7) and describe its growth promoting effects with E. coli. In addition, the corresponding conjugate (8) with a carbacephalosporin β-lactam antibiotic is described and evaluated for biological activity.