A simple and efficient synthesis of bis(α-aminophosphonates) has been developed by the reaction of aromatic aldehydes, 1,4-phenylenediamine and diethylphosphite in the presence of cellulose-SO₃H as catalyst under neat conditions at room temperature for 10-30 minutes. The synthesized compounds were screened for their antioxidant activity against DPPH, NO and H₂O₂ scavenging methods. All the compounds exhibited good to moderate activity.