A novel hidden reaction of the phenoxyl radical (C₆H₅O^•) with a specific daughter is found to significantly alter its hitherto accepted coupling reactions’ scheme. Transient characterizations and mechanistic evaluations in highly acidic to strongly alkaline aqueous medium reveal this concurrent reaction competing favorably in nanosecond–microsecond time-scale with the five distinct C₆H₅O^• RC₆H₅O^• reactions, which produce various phenolic end products as reported earlier (M. Ye and R. H. Schuler, J. Phys. Chem. 1989, 93, 1898). Presently, only the symmetric
4,4¢(-dioxo transient precursor, O=C₆H₅—H₅C₆=O that leads to the stable 4,4¢(-biphenol product, gets partially oxidized by a fraction of remaining C₆H₅O. The resulting secondary transient C₁₂H₉O₂ radical is generated at diffusion-controlled rate, k > 5.0x10⁹ M^-1 s^-1, and follows an independent chemistry. Consequently, when the previously reported five coupled end product distribution ratios were appropriately updated, the respective fractional values revealed a closer match for the symmetric 2,2¢(- and 4,4¢(-biphenols with their suggested coupling reaction branching probabilities based on the atomic spin-density distributions in the C₆H₅O^• radical (P. Neta, R. W. Fessenden, J. Phys. Chem., 1974, 78, 523). Results also suggest that in the remaining fraction, differential solvation in aqueous medium of various orientation-related encounter complexes (C₆H₅O. . .C₆H₅O) formed during coupling favors rearrangement only toward 2,4¢(-biphenolic product, at the cost of 2- and 4-phenoxyphenolic species.