With the required quinoline tethers in hand, three aziridines 3a-c were prepared by previously reported methods and the compounds were reacted under Pd catalysis in order to form a small compound library. This proved broadly successful, with 1-substituted tethers 11a-c reacting as expected to form tricycles 7aa-cc in good to moderate yield (Table ). Yields are unoptimised except for that for the reaction forming 7ab, which was shown to be scalable to 1 mmol without reduction in yield. While reactions of tert-butyl substituted aziridine 3c proceeded somewhat more slowly, as we have previously reported, all reactions were found to be complete within 15 h at 100 °C. Increasing substitution of the quinoline necessarily leads to an increase in electron density (i.e. moving from 11a to 11c) and might thus be expected to impact on the rate limiting Diels-Alder cycloaddition within the cascade process; however, little difference in conversion vs time profile was observed, suggesting all quinoline moieties are effective in activating this step. Reactions involving 2-substituted tether 15 proved somewhat more challenging, with reactions proceeding significantly more slowly and redoxbased side reactions competing at higher temperatures. However, increased reaction times led to isolable levels of product formation in all cases. As expected, the reaction to form tert-butyl ester 7dc proved to be the most challenging; however, this was improved by pre-mixing tricyclic aziridine 3c with the catalyst prior to addition of allylic acetate 15 following this initial allylation step was followed by a separate cycloaddition step at higher temperature. These conditions enabled isolation of the desired product in 18% yield, with this improved yield from pre-mixing (c.f. 1% without) suggesting that a mismatch in rates of oxidative addition may be present in the case of allylic acetate 15. Further, the reduced rate within the Diels-Alder reactions to form series 7dx suggests that the 2-substituted allyl component is appreciably less activated, potentially due to either reduced conjugation of the alkene with the quinoline moiety or increased steric demand. However, despite some reduction in these latter reactions, the process gave broad access to the compounds shown in Table , tolerating significant changes in electron density of the activating quinoline moiety and providing a diverse range of compounds from seven easily prepared building blocks in a single step. With this family of twelve compounds now available the photophysical properties could be investigated. The focus was to explore TSCT between the nitrogen atom on the cage and the quinoline moiety. Since the general effect of protonation on the two nitrogen atoms was expected to be similar to quinine MeCN and 0.1 M H2SO4 were chosen as solvents to allow for study of the doubly protonated and unprotonated forms of the compounds. This would allow the SARs to be built up around the changing parameters of the number of methoxy groups and N-aryl distance. Figures and show the excitation and emission profiles of the compounds at 20 µM concentration in MeCN and 0.1 M H2SO4. The absorption spectra for the compounds in the respective solvents can be found in the Supplementary Information Figures and. For the doubly protonated species (0.1 M H2SO4) the emission profile is pretty much the same for all compounds. In 0.1 M H2SO4 both the nitrogen atom on the cage and the nitrogen atom on the quinoline unit will be protonated, meaning that there is very low potential for TSCT. Given the similarities in structure the emission properties are very similar with the doubly protonated/methylated quinine emission as reported elsewhere. Interestingly the number of methoxy units on the quinoline unit affects the PLQY of the emission (Table ). With the monomethoxy series (7cx) showing the highest PLQYs consistent and at times exceeding the PLQY for quinine in 0.1 M H2SO4. However, having zero methoxy units or having two methoxy units serves to reduce this quantum yield to either 6-8% or 25-30% respectively. The position of attachment to the cage also does not seem to affect the quantum yield with the 7dx series being almost identical to the 7ax series. The PLQY in MeCN is very low and similar for all compounds, with slightly better performance observed for the 7bx and 7cx series. Of greater interest however is the spectral character of the compounds in MeCN. In this solvent neither of the nitrogen atoms should be protonated and thus we can unpack the behaviour of the lone pair on the electronic properties of these compounds. Considering the 7cx series first it can be seen that in MeCN there is only locally excited emission with an onset of 3.77 eV. Removing a methoxy group such as in the 7bx series the emission is still predominantly dominated by the LE emission but there are some beginnings of charge transfer emission in the lower energy part of the spectrum. Moving to the zero methoxy compounds (7ax and 7dx) the charge transfer emission dominates in MeCN, with strong charge transfer character particularly in the 7dx series. This is consistent with the lone pair of the nitrogen being spatially closer to the quinoline unit in the 7dx series compared to the greater distance observed in the 7ax series.