2-(4-Chloro and 4-fluorophenylamino)-2,4,4,6,6-pentachloro-1,3,5,2 lambda(5),4 lambda(5),6 lambda(5)-triazatriphosphinines and poly [bis(4-fluoropwhenylamino)phosphazene] were synthesized by reactions of 4-fluoroaniline and 4-chloroaniline with 2,2,4,4,6,6-hexachloro-1,3,5,2 lambda(5),4 lambda(5),6 lambda(5)-triazatriphosphinine and poly(dichlorophosphazene), respectively, in tetrahydrofuran under argon at -20 degrees C, followed by heating under reflux. The products were isolated by column chromatography and were characterized by FTIR, NMR (H-1, C-13, P-31), and mass spectra, termogravimetry, and high-performance liquid chromatography. Antimicrobial activity of the monomeric compounds and polymer against 9 bacteria and 5 yeast cultures was evaluated by the disk diffusion method in dimethyl sulfoxide relative to a number of commercial antibiotics and antifungal agents. Aminophosphazene derivatives exhibited a broad spectrum of activity against both Gram-positive and Gram-negative bacterial with a magnitude comparable to reference antimicrobial agents. The polymeric product turned out to be more potent than the monomeric compounds.