Charge‐Transfer Transitions Govern the Reactivity and Photophysics of Vicinally Diphosphanyl‐Substituted Diborapentacenes

2,3‐Difluoro‐5,14‐dihydro‐5,14‐diborapentacene (DBP) was endowed with two vicinal Ph(2)P groups by an S(N)Ar reaction at both CF sites using Ph(2)PSiMe(3). Computations reveal the ambipolar product P to undergo P‐to‐B charge transfer under ambient light irradiation. Consequently, P is prone to photooxidation by air, yielding the Ph(2)P(O) species PO. With S(8) or [Me(3)O][BF(4)], P furnishes the Ph(2)P(S) or Ph(2)P(Me)(+) derivatives PS or [PMe][BF(4)](2). Along the series P, PO, PS, and [PMe][BF(4)](2), the redox potentials shift anodically from E (1/2)=−1.89 V to −1.02 V (CH(2)Cl(2)). Thus, derivatization of the Ph(2)P group allows late‐stage modulation of the LUMO‐energy level of the DBP. Derivatization also influences the emission properties of the compounds, as PO shows green (521 nm) and [PMe][BF(4)](2) red (622 nm) fluorescence in C(6)H(6), while P and PS are dark. With CuBr and AgBr, P forms dimeric [M(μ‐Br)](2) complexes [PCu](2) and [PAg](2), which show pronounced metal‐to‐ligand charge transfer (MLCT), making P a promising ligand for photocatalysts.