A new amphiphilic polymer containing pyridine units was synthesized and characterized. The solvent-dependent conformational transition from extended transoid to helical cisoid was studied by absorption, fluorescence, and H-1 NMR measurements. The polar solvent promoted the formation of the helical structures. A metal ion or H+ could stabilize the ordered structure. Moreover, the solvophobically induced helical structure was stable to environmental stimuli. (c) 2006 Wiley Periodicals, Inc.