Several cofacial phthalocyanines (Pcs) with an Si−Si linkage were obtained by one‐step condensation of 1H‐isoindole‐1,3(2H)‐diimine with hexachlorodisilane as template in quinoline. They were characterized by gel‐permeation chromatography, IR, NMR spectroscopy, and mass spectrometry, and cyclic voltammetry. The results strongly suggest that we indeed obtained Pc dimers directly linked by an Si−Si bond using this novel concept of utilizing a compound/salt with an element–element bond as a template. The cofacial dimer structures are reasonably supported by X‐ray absorption near‐edge structure (XANES), electronic absorption and magnetic circular dichroism (MCD) spectra, and molecular orbital (MO) calculations. Interestingly, they show an electronic absorption spectrum very similar to that of silicon tetrabenztriazacorrole (SiTBC).

A new concept widely applicable in organometallic chemistry has been introduced for the preparation of cofacial macrocyclic dimers or oligomers. The most notable feature is the use of dimetal or oligometal salts/compounds as templates. In order to exemplify the advantage of this method, a cofacial diphthalocyanine linked by an Si—Si bond has been synthesized in 30% yield in a one-step reaction using hexachlorodisilane as a template and characterized. The cofacial dimer structures are supported by various spectroscopic techniques, including electronic absorption, magnetic circular dichroism, nuclear magnetic resonance and differential pulse voltammetry. However, the unusual phenomenon of a red shift of the main band in the Soret band region was observed.