More quantitative theory experiment can be reached by considering 0-0 energies (for emissive dyes) and band shapes. For the latter, one can find in Fig. the theoretical band shape of 7 + , and it clearly fits the experimental one with a marked shoulder and a molar extinction coefficient fitting the experimental value as well. As 0-0 energies, theory returns 2.69 eV, 3.17 eV, 3.00 eV, 2.88 eV, 3.06 eV, and 2.99 eV in the 7 + to 12 + series. For the three cases in which it can be compared to experiment, namely 9 + , 10 + , and 12 + , the discrepancies between theory and experiment are of the order of 0.2-0.3 eV, which is usual for such level of theory. It has been shown on various cyanines dyes that the nature of the counterion strongly impacts the absorption in apolar solvents and in solid state. Here, the band shape is not affected by the nature of the counterion (Fig. ). This absence of interaction is due to the bulkiness of the tetravalent P-atom which prevents the ions to strongly interact, in contrast to the "classical" cyanines, in full agreement with the structural study based on X-ray diffraction (vide supra). This feature is a clear advantage for considering further applications in the solid state, as the absorption properties will be similar to those in diluted solution. No complex anion engineering will thus be necessary to maintain the cyanine behaviour.