Thermally activated delayed fluorescence (TADF) constitutes a promising route toward creating organic electroluminescent materials with the potential to obtain 100% internal quantum efficiency through the possibility of harvesting both singlet and triplet excitons. On a microscopic level, TADF is governed by the reverse intersystem crossing (rISC) process whereby a nonemissive molecular triplet excited state is converted into an emissive singlet state capable of efficient luminescence. Most prominently, the rISC process depends on the energy gap (∆E ST ) between the lowest excited singlet and triplet states, which enters exponentially into the rate expression and can be seen as an effective activation energy to the TADF process. Other influences are related to spin-orbit coupling (SOC), enabling the formally spin-forbidden rISC process, and the oscillator strength ( f ) of the emitting singlet state. All three properties crucially depend on the state character where enhanced charge transfer (CT) is expected to lower both ∆E ST and f . SOC, on the other hand, is promoted by a difference in state character between the singlet and triplet states. More recently, multipolar systems have been introduced where one acceptor unit is connected to two or more donor units and vice versa. Aside from the above considerations, the possibility of symmetry breaking in the excited state is particularly intriguing in such multipolar systems. The intricate photophysics of TADF emitters poses severe challenges for its computational description while also providing an ideal test bed for evaluating the newest computational tools. The importance of CT states already makes it clear that the application of time-dependent density functional theory (TDDFT) is challenging and expected to affect energies as well as state characters. Suggestions for addressing this problem range from empirical corrections to optimal tuning of range-separated functionals to the avoidance of TDDFT altogether in favour of unrestricted ground-state DFT. Furthermore, state-specific excitedstate solvation effects have to be described at a high level considering that the common linear-response polarizable continuum model (LR-PCM) is inadequate for CT states with large electronhole separation and does not even provide any correction beyond zeroth order to triplet states due to their vanishing transition density. SOC also plays a role, having an intricate dependence on the state character where small amounts of mixed character lead to appreciable coupling. Finally, the importance of vibronic coupling between the locally excited (LE) and CT triplet states has been emphasised providing new dynamical routes to rISC.