The central BiI atom forges single bonds with the terminal atoms instead. The remaining two valence electrons are delocalized over the three centers in the core (Figure ). This defines a bond-order of 1.5 between the BiII/BiI pairs, consistent with the structural parameters and the discussion above. In terms of charge delocalization, the outer BiII centers carry slightly more positive charge (natural population analysis (NPA) charge ~ +0.7) than the bridging BiI (NPA charge ~ 0.15). These charges add up to more than one full positive charge due to the charge transfer of the BiII centers to the carbon atoms. Overall, this electronic structure resembles the charge distribution typically described in π-allyl cations. The UV-Vis absorption spectrum of compound 2 shows absorption bands at 27701, 19305, 12887, and 10000 cm -1 (Figure , top). This was also calculated using time-dependent DFT (TD-DFT). These allelectron calculations were performed with and without the inclusion of spin-orbit coupling (SOC) using the X2C-relativistic Hamiltonian and the spin-orbit mean-field (SOMF) operator together with finite nucleus and picture change corrections. Singlet-and triplet excited states calculated from the scalarrelativistic TD-DFT calculation were allowed to interact via the SOC using quasi-degenerate perturbation theory (QDPT). The resulting calculated spectra (Figure , middle and bottom) compares favorably with experiment if the SOC is included. In particular, the trailing intensity observed between 8000 and 12000 cm -1 results from a series of singlet-to triplet transitions that borrow intensity via the SOC while the main bands observed around 13000 cm -1 and 19000 cm -1 are dominantly singlet-singlet based. Interestingly, the calculated spectra predicts that the observed intensities in the UV-Vis spectra derive from transitions that all involve the same acceptor orbital, namely the LUMO of the Bi3 core. The first two excited states are of (Bi)3 σ → (Bi)3 π * and (Bi)3 π → (Bi)3 π * in nature, and account for the bulk of the intensity observed experimentally at 13000 cm -1 . The remaining transitions all account for a complex set of ligand-to-metal charge transfer into the (Bi)3 + π * acceptor orbital. Yield and distribution of products 6 and 1 were determined by 1 H NMR analysis of the crude mixture using 1,3,5 trimethoxybenzene as the internal standard.