Vanillin–chitosan biodynamers have been prepared and structure–morphology correlations revealed the pathway of progressive incorporation of the aldehyde onto chitosan backbones. Such dynamic biopolymers or biodynamers, generated from reversibly interacting components, o␣er the possibility to address the dynamic covalent behaviour of the reversible imine-bond formation/hydrolysis equilibria between vanillin and chitosan polymeric backbones. The reaction takes place with very low conversion in acidic aqueous solutions (7–12%), but the imine bond formation is amazingly improved ($80%) when the reaction takes place while solution–solid state transition and solid state phase-organization events occur. The chitosan–vanillin biopolymeric ␣lms described here present interesting Candida albicans antifungal activity compared with other common bacterial strands, which suggests the implementation of these biocompatible materials as thin layer protecting systems for medical devices.