Transient absorption (TA) spectroscopy was used to study the excited state lifetimes of 1a and 3. These measurements were used to assess the relative rates of NRD between the T-shaped and α-diimine Pd complexes; since both complexes appear to have similar barriers to Pd-C cleavage and do not undergo significant fluorescent decay, we hypothesize that differences in their excited state lifetimes are likely due to different rates of unproductive NRD. In addition, TA measurements can also provide information about the magnitude of charge transfer between ground and excited states. To ensure that the amount of photodegradation was minimized to the extent possible, the intensity of the laser was optimized and pre-and post-scan absorption measurements were performed. A ground state bleach from 375-410 nm is apparent for 1a (Figure , a) coinciding with the absorptive region in the absorption spectrum. A broad excited state absorption is also evident from 410 to beyond 610 nm, which decays within ca. 50 ps (Figure , b). This latter feature was assigned as the excited state decay of 1a. A long-lived feature peaked at 450 nm follows, which persists out to the nanosecond timescale. This is consistent with the difference absorption obtained from pre-and post-scan steady-state measurements (Figure ). This feature is consequently assigned to a photodegradation process. Please do not adjust margins