A comparison of the crystal and DFT-optimized structures of 11 reveals a high degree of agreement. This is evidenced by a detailed comparison of the bond lengths, as shown in Figures and. Both isomers of 15 were subjected to DFT studies and the final geometries are presented in Figure . The triheterocyclic braces involving two pyrrole and cyclopentadienyl rings demonstrate planar geometry. In contrast, selenophene is tilted from the macrocyclic plane. The geometry of the transient species 15-t0 with the selenophene ring located in the carbaporphyrinic plane was also considered. The selenophene tilt angles from the four meso-carbon atoms plane equal -37.2° (15-A0) and 35.3° The electron density of delocalized bonds (EDDB) was employed to investigate cyclic π delocalization across conjugated bonds in 11 and 15, with 9 and 14 serving as comparative controls (Figures and). The EDDB isocontour maps of 11 and 11-H2 2+ reveal the presence of localized π-conjugation on the cyclopentadienyl ring, which does not disrupt the π delocalization throughout the carbaporphyrin structure (Figures and). It is observed that effective π-conjugation occurs through the 1,3substituted ruthenocene moiety. The aromaticity of ruthenocenoselenaporphyrin 11 and its dication 11-H2 2+ was further analyzed using nucleus-independent chemical shifts (NICS) calculations. The analysis of the NICS 2D map of 11 revealed negative values within the inner cavity of the macrocyclic ring (Figure ). However, these values were significantly less negative than those observed for the control 9-I (Figure ). After protonation in 11-H2 , the aromaticity features became more visible (Figure ). The NICS(0) values were calculated for molecules 11 and 11-H2 2+ at the centers of macrocycles (Figure ). After binding of the [RuCp*] + moiety to 9, the corresponding NICS(0) values are noticeably less negative -8.5 in 11 and -10.0 in 11-H2 2+ compared to 9 (-16.7 in 9-I, -14.8 in 9-II).