DiKTa3 emits at lPL of 491 nm (FWHM of 52 nm/0.26 eV) and has a moderate DEST value of 0.24 eV in toluene and is very poorly emissive. The 1 wt% doped film of DiKTa3 in PMMA exhibits TADF. The density functional theory calculated (M062X/6-31G(d,p)) chiroptical properties based on the optimized geometry predict gabs values of 2.1 × 10 -2 for the S0-S1 transition due to a cosq value of 1. However, the predicted value differs considerable from the measured one in toluene (gabs of 6.8 × 10 -4 ). This is the result of DiKTa3 adopting a conformation that is not C3-symmetric; indeed, the calculated gabs value using geometry obtained from the single crystal structure is 8. moments and the corresponding gabs value. These results may also explain why many triple helicenes show low gabs values of around 10 -3 . Results & Discussion