Lignin-derived chemicals, such as vanillin and syringaldehyde, are representative bio-renewable monomer building blocks for polymer chemistry. When considering the chemical structures of vanillin and syringaldehyde, they instinctively feature aldehyde groups in their molecular structures. Since aldehydes are some of the most important reactants in multi-component reactions (MCRs), we now report the Kabachnik-Fields three-component reaction (KF-3CR) between amines, phosphites, and polymers featuring vanillin and syringaldehyde. The successful KF-3CR of the polymers featuring vanillin and syringaldehyde proceeded with a practically perfect consumption of the starting aldehydes, essentially affording polymeric α-amino phosphonates.