Active metals induce a variation of the conformation of zwitterionic conducting polymer poly(3-octylpyrrole)squaraine in solution. Evidence from infrared, visible and photoluminescent spectra and from small-angle X-ray scattering profiles unambiguously confirms the isomerization of this polysquaraine induced by the surfaces of active metals. Unlike the irreversible change induced by cations in solution, the folded conformation induced by active metals reverts to its original structure on eliminating contact between the metals and the solution. Accompanied by altered optical properties, this reversible structural modification of the zwitterionic polysquaraine induced by active metals represents a new chemical and physical process. (C) 2010 Elsevier B.V. All rights reserved.