During the kinetic investigations of our previous study on photosensitized fluorination reactions, we discovered an induction period where scarcely any product forms. Subsequently, we observed that increasing the loading of substrate (i.e. photoactive auxiliary) decreases this induction period. In this study, however, we took a different approach. We presumed that an active species was formed not at the beginning of the reaction but during the reaction that afterwards accelerates the product formation (Scheme 3, A). This prompted us to examine adding the two main reaction products -The two main product i) the fluorinated alkyl chain product 2a and ii) H-TEDA(BF 4 ) 2 -at the start of the reaction. Addition of 2a to the reaction mixture did not influence the induction period of ~8.3 h (Scheme 3, B). However, when we added 1.5 eq. of H-TEDA(BF 4 ) 2 to the reaction mixture prior to turning on the light, the reaction had a substantially shorter induction period of ~1.7 h and a profile typical of a firstorder reaction (Scheme 3, C). Moreover, the rate of formation of 2a and its overall yield was higher with the addition of H-TEDA(BF 4 ) 2 (Scheme 3, D). Thus, it was highly encouraging to find that adding exogeneous H-TEDA(BF 4 ) 2 not only minimizes the induction period, but also improves the efficiency of the reactions vs the presence of nascent H-TEDA(BF 4 ) 2 generated in the reaction. In commercially supplied SF ® samples, trace (2%) H-TEDA(BF 4 ) 2 was present as an impurity; however, this is insufficient to observe any reaction promotion.