Xanthone and 1-hydroxyxanthone polymers were prepared by the Kostanecki reaction on salicylic acid-formaldehyde and 4-(amino, chloro, and bromo)-salicylic acid-formaldehyde polymers, respectively, with phenol and resorcinol. All the xanthone polymer samples were characterized by elemental analysis, by IR spectral study, and by TGA. Xanthone polymers were also screened for their antifungal activity against a variety of fungi.