The first CPPs ( [9]CPP, [12]CPP, and [18]CPP) were synthesized using a strategy where cyclohexadienes were employed to afford intermediates that could more easily accommodate the curved structure prior to aromatization in the final step. A complementary strategy involves the formation of platinum complexes as precursors that then can be demetalated to form the CPP by reductive elimination. Seminal contributions from Bertozzi et al., Jasti et al., Itami et al., and Yamago et al., amongst others, have demonstrated how the synthesis of CPPs can be scaled and how these structures can be elaborated further to generate compounds with desirable optoelectronic properties. Majima et al. systematically investigated the size dependence of the CPP on the absorption, fluorescence and phosphorescence spectra from [8]CPP to [13]CPP and found that although the absorption spectra were rather insensitive to the size of the CPPs, larger Stokes shifts were observed for the smaller CPPs as the singlet and triplet state energies increased with the number of benzene units. The size dependence can be explained by the stronger structural relaxation from the Franck-Condon state for smaller CPPs, which also leads to the very low ΦPL of [8]CPP (<10%) compared to 66% and 72% for [12]CPP and [13]CPP in THF, respectively. The CPPs show reversible oxidation waves in the cyclic voltammograms (CVs), with smaller CPPs possessing cathodically shifted oxidation potentials (i.e., destabilized HOMO levels), which match the density functional theory (DFT) calculations. The DFT calculations also predicted that the LUMO levels would be stabilized with decreasing unit number within the [n]CPP; however, reduction waves could not be observed within the potential window of tetrachloroethane. The optoelectronic properties of CPPs can be tuned by decoration with electron-donating or withdrawing groups. Jasti et al.