Resorcin [4]arenes are cone-shaped phenolic macrocycles, well known for their electron-rich cavities and affinity for organic cations. While some of them have also been shown to bind anions, they acted in these cases as classic OH hydrogen bond donors. In the absence of OH groups (e.g. in O-alkylated derivatives), no significant interactions of resorcinarenes with anions could be expected. Nevertheless, the Dalcanale group noticed weak interactions of large anions (PF6 -) with acetal CH groups in the upper rim, and some of us found weak but non-negligible interactions of anions with 7 via aromatic CH groups in the lower rim. The latter observation was particularly surprising because resorcinols are classic electron-rich aromatic rings that have not been previously considered capable of CHanion interactions. Intrigued by this observation we aimed to rationally enhance anion binding via the aromatic CH groups at the lower rim of resorcin [4]arenes, and for this purpose, we designed receptors 1-4 (Fig. , Ha marked in green). We assumed that the para-positioned -NO2 groups in 1-4 would reduce the electron density at Has by both resonance and induction effects, while the -OCH2/OH groups would donate electrons, but mostly to their ortho-and para-positions. However, the net effect of these contributions is difficult to predict based on qualitative arguments, and therefore we performed DFT calculations (DFT B3LYP/dgdzvp in THF) for a series of model compounds (VI-XI, Fig. ), newly designed receptors (1-4, Fig. ), and previously known receptors (I, II, Fig. ), to analyze structural determinants of the two parameters that are relevant for anion binding: dipole moment () and electrostatic surface potential (ESP).