The initial discussion will focus on the room temperature cwESR results obtained for the monoradical reference system, AAF, in liquid solutions of dichloromethane. The experimental and simulated cwESR spectra are shown in figure The room temperature spectra of the C labelled and unlabelled AAF systems are typical of organic radicals with transitions centred around 𝑔 e ≈ 2.0023. The largest hyperfine splitting in panel (a) is caused by couplings to four approximately equivalent protons with a Fermi contact interaction 𝑎 iso ≈ 10 MHz. For the labelled system in panel (b), a Fermi contact interaction of ∼ 57 MHz to C causes a 'doubling' of the spectrum. These hyperfine parameters are broadly consistent with the Density Functional Theory (DFT) results shown in the SI. The DFT calculation predicts a spin density localised primarily on the fluorenyl (F) side of the molecule with minimal leakage onto the anthryl fragments. According to DFT, the four 10 MHz 1 H couplings belong to the ortho and para protons relative to the carbon atom with the largest spin density -i.e. marked with a dot in figure (see also ENDOR discussion below). The next largest DFT predicted couplings correspond to the meta protons, and are represented in the spectral simulations as the two additional sets of two protons with couplings of ca. 2 MHz.