DHFR-IN-9 (compound 8A) is a dihydrofolate reductase (DHFR) inhibitor that affects purine and thymidylate biosynthesis in cell proliferation and growth. DHFR-IN-9 inhibits methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 ( IC 50 =0.25 μg/mL) and has anti-infective effects in mouse models of systemic infection and thigh infection caused by it (dose: 2.5 mg /kg, 5 mg/kg; ip). DHFR-IN-9 has stronger anticancer activity than paclitaxel (Y-B0015) in a mouse model of breast cancer (dose: 2.5 mg/kg; ip; once every 3 days).