Furthermore, unlike reported examples using embedded hydrogen-bond acceptors to induce NH4 + binding, 2 was shown to exhibited preferential recognition to NH4 + guest by a unique combination of cation/polar-𝝿 type interactions. Notably, such selective ammonium recognition has been particularly challenging in the past. Therefore, this work provides an alternative design principle employing solely N-H⋯𝝿 interactions for ammonium detection.