a Solution absorption and normalised photoluminescence (PL, solid lines) spectra of COT*, mCP and mCP-COT in toluene (inset shows the weak COT absorption). Excitation wavelength = 290 nm. b Normalised photoluminescence of mCP (blue line) and mCP-COT (red line) at 77 K. At this low temperature, phosphorescence seen as peaks from 400 to 500 nm in mCP (yellow highlights) are not observed in mCP-COT, indicating efficient quenching of the triplet excited-state of the mCP moiety within mCP-COT. Excitation wavelength = 300 nm. *no PL was observed for COT.