The CH center dot center dot center dot pi hydrogen bonds (HBs) between trimethylamine (TMA) and an assortment of pi-systems are generally weaker than those in which CF3H serves as a proton donor, despite the larger number of CH groups available to serve as donors in the amine. The added positive charge of tetramethylammonium (TMA+) enhances the binding energy by a factor between 4 and 7. The strongest such interaction for TMA+ occurs with indole, bound by 15.5 kcal/mol. Changing from ionic CH center dot center dot center dot pi if to NH center dot center dot center dot pi further strengthens the interaction. Conjugation of the pi-system improves its proton-accepting capacity, which is further enhanced by aromaticity. Dispersion plays a major role in CH center dot center dot center dot pi HBs: It is the prime contributor in the neutral HBs of TMA, and comparable to Coulombic forces for CF3H and even in ionic CH center dot center dot center dot pi HBs of TMA+. Many of the results can be understood on the basis of a combination of electrostatic potentials and charge transfers.