We report here the design, synthesis, and antibacterial activities of novel classes of compounds containing chiral 1,3-oxazinan-2-ones and oxazolidinones as the basic core structures. These compounds are tertiary amines containing the core structures and two aryl substituents. Several of these molecules exhibit potent antibacterial activities against the tested Gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Bacillus subtilis. These compounds represent new structure scaffolds and can be further optimized to give new antibacterial agents with structures significantly different from those of existing classes of antibiotics.