A method to covalently attach combinations of six different B vitamins provided an avenue to new functional thermosets without multi-step coupling reactions. The melt polymerization strategy required no organic solvent and facilitated covalent attachment of OH (B 1 , B 2 , B 5 , B 6 ) or COOH (B 7 , B 9 ) groups on B vitamins via Fischer esterification. Characterization of model reactions with LC/MS, FTIR, and GPC confirmed covalent attachment. Based on control experiments, B vitamins demonstrated unexpected thermal stability and appreciable solubility in the melt polymerization. This approach was demonstrated with citric acid and diglycerol, but has wide-ranging potential for other polar monomers with negative octanolwater partition coefficients (LogP).