New 1D-chain copper(I) complex [Cu2(μ-(3,4,5-MeO-ba)2bn)(μ-I)2]n (1), where (3,4,5-MeO-ba)2bn = N,N′-bis(3,4-dimethoxybenzylidene)-butane-1,4-diamine, involving a new bidentate Schiff-base containing a flexible spacer (=N–C–C–C–C–N=) has been synthesized and characterized by elemental analyses (CHN) and FT-IR spectroscopy. The crystal structure of 1 was determined from single-crystal X-ray diffraction analyses and shows the (3,4,5-MeO-ba)2en acts as a bridging ligand with the nitrogen atoms of the two imine functions and leading to the dinuclear [Cu2((μ-(3,4,5-MeO-ba)2en)] groups. Such dinuclear [Cu2((μ-(3,4,5-MeO-ba)2en)] groups are bridged by two iodine anions [(μ-I)2] to form a neutral 1D-chain copper(I) iodide coordination polymer. The coordination polyhedron about the copper(I) center in 1 is best described as a distorted trigonal planar. Thermogravimetric analyses reveal the thermal stability and decomposition pattern of 1.