To test our hypothesis the iptycene 2 was synthesised. Three factors led to the selection of this system: 1) The opportunity for comparison with the homologous TADF fin 1, 2) the facile synthesis (Scheme S2.1) of quinoxaline-based iptycenes, and 3) the ubiquity of the pyrazine motif in TADF materials. The NMR characterisation of the compounds can be found in the supplementary information (Figures S3.1-S3.5). The structure of 2•7CHCl3 was confirmed by single crystal X-ray diffraction (Figures and.7 and Table .3). 2 crystallised as a CHCl3 heptasolvate, presumably due to the large internal free volume of iptycene structures. The structure of two, polymorphic, CDCl3 mono-solvates of 1 were also determined using synchrotron radiation (Tables S4.1-S4.2 and Figures S4.1-S4.6).ⱡ