The situation becomes more complex with two (or further) heteroatoms E and E' with in-plane lone-pair electrons because the excitation can be out of either the in-phase or outof-phase combination of the local n(E) and n(E') orbitals. Throughout we discuss the lowest n,* state, yet in a few cases we explore also the second lowest in order to establish an unambiguous comparison between analogous n,* states of a subset of the mono-and diheteroaromatics. Moreover, the lowest 3 n,* state is not necessarily the T1 state. Here, we found that 6-MR heteroaromatics often have T1 states of n,* or * character, while the T1 state of 5-MR heteroaromatics (as mentioned above) mainly are of  character as the inplane n orbitals are of lower and the * orbitals of higher energy than in the 6-MR heteroaromatics (see section 3.7, Supporting Information).