A new class of novel 7,8‐dihydroquinolin‐5‐(1H,4H,6H)‐one derivatives (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k) were synthesized by the one‐pot four‐component condensation of dimedon, α‐ionone, ammonium acetate, and benzaldehyde derivatives. The structures were characterized by elemental analysis, IR, 1H‐NMR, and 13C NMR spectral studies. All the title compounds were screened for antioxidant properties and some of them found to exhibit potent in vitro antioxidant activity. J. Heterocyclic Chem., (2011).