The absorption of the electrochemically generated radical cation 2 + • is characterized by the appearance of new bands in the visible and NIR regions (Fig. ), characteristic of a highly delocalized organic radical. These new transitions subsequently disappeared upon reduction to the neutral derivative (Fig. and Fig. ). Qualitatively, the evolution of the spectra upon successive reductions is reproduced by TD-DFT (Fig ). The absorption spectra of 2 2+ was further recovered upon restoring the initial potential (Fig. ), illustrating the switching ability of this derivative. EPR was measured after chemical reduction of 2 2+ with Zn powder (Fig. ). This unambiguously confirmed the organic radical nature of the 2 + • with g-factor values of 2.0032. The hyperfine structure of the experimental EPR spectrum is well reproduced (Fig. ) taking into account the coupling of the unpaired electron with the two equivalent phosphorus atoms and the two sets of equivalent Hydrogen atoms. This demonstrates that the radical is fully delocalized on the bisphosphapyrenic scaffold. The computed spin density in the radical cation 2 + • (Fig. ) also fully supports this observation. The equalization of the C-C bond lengths in the phosphacycle (evaluated by DFT, Table ) are consistent with the switching between  4 -P + cyclic phosphoniums for 2 2+ and  5 -phosphinine for 2. Accordingly, the aromaticity in the P-heterocycle increases upon reduction (NICS(0)(2 2+ )= +4.6; NICS(0)(2)= -2.6, Fig. ). 17 Altogether, these results illustrate that 2 2+ possesses the characteristics for a new generation of electro-responsive multi-stage organic system based on organophosphorus derivatives. In conclusion, a straightforward synthetic route to dicationic Pcontaining PAH 2-6[OTf]2 is described. The absorption and emission signatures of these compounds are changed with the -conjugated segment, especially for the -curved 6[OTf]2. In addition, their particular structures make that 2-6[OTf]2 possess fluorescence both in solution and in the solid-state. Furthermore, 2-6[OTf]2 are good electron acceptors with two "viologen-like" easily accessible reduction states. 2 2+ was used to study the three redox states by a combined experimental (spectrolectrochemical and EPR) and theoretical study. In particular, EPR unambiguously proved the formation of the organic radical 2 + •. This first communication highlights the great potential of these novel organophosphorus derivatives for further "viologene-like" switching applications, taking advantage that, 2-6[OTf]2 are good luminophores. In addition, the simplicity of the synthetic approach paves the way toward the preparation of a virtually unlimited panel of redox-active P-derivatives based on (twisted) acenes, helicenes, nanographenes etc This work is supported by the Ministère de la Recherche et de l'Enseignement Supérieur, the CNRS, the Région Bretagne, the ANR (Heterographene ANR-16-CE05-0003-01). Y. Molard / G. Taupier (Scanmat-UMS 2001) are thanked for PLQY measurements. This work used the computational resources of the CCIPL supercomputing center installed in Nantes. T. Guizouarn (ISCR) is thanked for the EPR measurements. M. Cordier and V. Dorcet (CDIFX, ISCR) are thanked for X-ray diffraction.