Five new cyclopentane-condensed chromones, coniochaetones G-K (1-5), along with four known compounds -penicillone C (6), penicillanone (7), conioxanthone A (8), and pinselin (9) were isolated from the crude extract of marine-derived fungus Penicillium oxalicum. The structures of 1-5 were elucidated by NMR, MS, ER, UV, and CD spectra. Metabolites 1-5 were evaluated for cytotoxicity, antibacterial, and antifouling activities.