Adsorption isotherms of N(2), O(2), CO(2), and Xe on a flexible microporous coordination polymer, CPL-2 [Cu(2)(pzdc)(2)(bpy)]center dot(pzdc = pyrazine-2,3-dicarboxylate; bpy = 4,4'-bipyridine), possessing bellows-shaped one-dimensional channels were measured. A nonintegral number of each of the N(2), O(2), CO(2), and Xe molecules can be accommodated in each unit pore, which indicates that all guest molecules are accommoda dated in the so-called "incommensurate fashion". in situ synchrotron X-ray powder diffraction patterns of CPL-2 with guest molecules were recorded. The unit cells were determined from each pattern. It Was found that the host CPL-2 exhibits different crystal transformation with the accommodation of each guest molecule. This indicates that, even in the case of incommensurate adsorption, the flexible framework of a microporous coordination polymer can transform each pore to suit different guest molecules. (C) 2009 Elsevier Inc. All rights reserved.