Abstract We report the synthesis and X‐ray characterization of N 9 ‐ and N 6 ‐decyladenine hydrochloride salts. The latter exhibits interesting anion–π interactions, which are responsible for crystal packing. In contrast, the former does not present any anion–π interactions; the anion is stabilized by hydrogen‐bonding interactions. Finally, a theoretical study of the different binding modes observed in the solid state is useful to explain the experimental findings.