An unprecedented twofold interpenetrating (3,4)-connected topology of the Cu(3)L(4)-type metal-organic framework was prepared using N,N',N''-tris(4-pyridinyl)-1,3,5-benzenetricarboxamide (L) as a trigonal three-connection node and the copper(ii) ion as a square planar four-connection node, where the framework contains remarkably large 1-D solvent channels.