This Communication reports simultaneous tracking of structural and kinetic information for the photoinduced elimination reaction of 1,2-diiodotetrafluoroethane in solution by transient X-ray diffraction. The transient structure of center dot CF2CF2I is determined to be a classical mixture whereas center dot CH2CH2I is bridged. Compared with the gas phase reaction, the secondary dissociation of center dot CF2CF2I into C2F4 and I is slowed down by a factor of 6 in solution. Transient X-ray diffraction offers a complementary method for capturing transient structures in solution which might be invisible or "optically silent" in time-resolved optical spectroscopy.