The unprecedented μ 3 - and μ 4 -bonding modes of NH 2 pyz (NH 2 pyz=2-aminopyrazine) are observed for the first time in a novel 3D Ag(I) coordination polymer [Ag 7 (NHpyz) 6 (ClO 4 )] n (1) which was obtained by reaction of Ag 2 O, NH 2 pyz and NaClO 4 in H 2 O/CH 3 OH/NH 3 media under ultrasonic treatment. Compound 1 is a 3D framework with infinite 1D Ag belts incorporating diverse Ag···Ag interactions. Moreover, 1 exhibits photoluminescence maximized at 494nm upon 300nm excitation at room temperature, which may be mainly assigned to ligand-to-metal charge transfer (LMCT) mixed with metal-centered (d-s/d-p) transitions. Semiconducting behavior of 1 was also measured at room temperature with σ value of 6.78×10 −6 Scm −1 .