An octamolybdate-containing noncovalently assembled framework with the formula (Hcpy)3[Ag(β-Mo8O26)] (1) (cpy = 4-(5-chloropyridin-2-yl)pyridine) is synthesized and characterized. Compound 1 comprises a three-dimensional supramolecular network constructed from one-dimensional {[Ag(β-Mo8O26)]3−}∞ anionic chains and protonated cpy cationic layers. The inorganic chain only constructed by the building block [β-Mo8O26]4− linked only via a single Ag+ ion is unusual. The extensive and efficient face-to-face π···π interaction in these aromatic N-heterocyclic systems is facilitated by the neighboring electron-withdrawing chlorine atom. Anionic shape and size also play an important role in the resulting supramolecular arrangement.