Tara‐decorated terpyridines 1–3 and their 1:2 Co2+ [Co(L)2](ClO4)2 (L = 1–3) and Co3+ complexes [Co(L)2](ClO4)2(SbCl6) (L = 1,3) are reported. The solid‐state complex metrics of [Co(3)2]2+ and [Co(1)2]3+ indicate an assignment as spin‐quartet Co2+ or spin‐singlet Co3+, which is in accord with DFT and 1H NMR studies. Vis‐NIR spectra of 1[Co3+(L)2]3+ show characteristic Tara→Co3+ charge‐transfer bands, giving no direct indication of L‐based oxidation events, irrespective of the solvent. Theoretical studies reveal no charge transfer induced spin transition in [Co3+(L)2]3+, although a substantial decrease of the HOMO‐LUMO gap prevails in [Co3+(1)2]3+ as compared with [Co(tpy)2]3+. The destabilisation of the HOMO is not sufficient to allow an equilibration among closed‐ and open‐shell formulations. The computed singlet‐triplet and singlet‐quintet splitting in [Co(1)2]3+ renders these open‐shell formulations to reside only moderately above the ground state. Design criteria are derived from this analysis aiming at a further stabilisation of the open‐shell species through implementation of more strongly electron releasing Tara substituents.

The one-pot synthesis of zinc isoporphyrins from pyrrole, an aryl aldehyde and zinc acetate was investigated with regard to the formation of by-products. The optical spectra of the product mixtures differ strongly from each other depending on the aldehyde used and the water content in the solvent mixture of the condensation step. The compounds belonging to the two most prominent bands at approx. 500 nm and at approx. 640 nm could be isolated and structurally characterised. These are the homoleptic complexes (dipy) 2 Zn with a dipyrrolic ligand, and unexpected zinc-tripyrrin species (trpy)ZnCl, respectively. The tripyrrin species further react under the conditions of chromatography to green intermediates and yellow end products, whose mass spectroscopic investigations indicate dimers and loss of one ZnCl 2 equivalent. The final products could be crystallographically identified as zinc-porphodimethene complexes and analysed with respect to the stereochemical situation and optical behaviour. In one case, the green intermediate form could be enriched. The investigations indicate a helical pentapyrrolic zinc complex with a noncoordinated pyrrolyl side arm and give clues to the stereochemical course of the stepwise dimerisation.

The Front Cover shows the Ishihara test plate of a dimeric zinc tripyrrin complex. This compound is a side product of the Adler‐Longo porphyrin synthesis, which has been overlooked for more than half a century. It has now been found to act as the key intermediate in the formation of branched oligopyrroles like porphodimethenes. The detection and isolation of the metalated tripyrrin and the unraveling of its special reactivity were only possible after attempting the use of zinc acetate as template reagent during the oxidation step. More information can be found in the Full Paper by M. Bröring and co‐workers.