The driving force dependence for CT in photooxidant-bridged DNA hairpins is determined from time-resolved transient absorption studies of a series of five stilbene-derived photooxidants and four hole acceptor bases, following both charge separation (filled) and charge recombination (empty). Case I,II (circles): donor and acceptor are in contact. Case III,IV (triangles): donor and acceptor are separated by two TA base pairs. Case I,III are fit only to charge separation rates (dotted), while Case II,IV are fit to both charge separation and charge recombination rates (solid). Similar reorganization energies, about 1 eV for the nuclear reorganization energy and ~0.2 V for the solvent reorganization energy, are found for both Case II and Case IV. Reprinted with permission from Reference 167. Copyright American Chemical Society.