To understand the stark difference between o-ICz-PI and p-ICz-PI we used the fragment orbital interaction approach that had previously characterized the competition between twisted and planar intramolecular charge transfer states in a range of D-A chromophores. These simulations demonstrate how sensitive the molecular electronic structure can be to bonding and anti-bonding patterns and that even in a fully-rigidified, co-planar D-A molecule, the CT state can be stabilised making it possible to achieve TADF, counter to previous thinking about these photophysical phenomena. Femtosecond induced absorption measurements further reveal o-ICz-PI to have an instantaneous induced absorption at 570 nm from an initial LE state; this is a more localised state compared to that seen in p-ICz-PI, rapid formation within 700 fs of a new state that absorbs at lower energy (at 660 nm) is observed which we ascribed to the formation of the CT excited state (Figure and Supplementary Fig. ). In DCM, this state at 670 nm has much stronger intensity than in MCH, but the formation rate is slower, ascribed to inductively slow charge reorganisation due to the solvent shell inertia (Figure and Supplementary Fig. ). The lifetime of the excited state is concomitant with the fluorescence lifetime measured. The induced absorption at 670 nm (in DCM) or 660 nm (in MCH) is never lost indicating a high level of electronic decoupling of the D and A fragments, independent of solvent polarity, indicating that the broken conjugation effect can fully stabilize the ICT excited state, as predicted by our calculations.