Diffusion-ordered NMR spectroscopy (DOSY) is a versatile and powerful NMR technique and a noninvasive analytical method for mixture analysis that does not require prior physical separation of the analysis. In our search for new metabolites from natural resources, DOSY was applied for constituent analysis of crude bromopyrrole fractions separated from an Okinawan marine sponge Agelas sp. (SS-1056) so that two new bromopyrrole alkaloids, agesamides A (1) and B (2), have been isolated. The structures and relative stereochemistry of 1 and 2 were elucidated fromspectroscopic data. Furthermore, two new bromopyrrole alkaloids, nagelamides J (3) and K (4), have been isolated from another Okinawan marine sponge Agelas sp. (SS-1077), and the structures and relative stereochemistries were elucidated from spectroscopic data. Nagelamide J (3) is the first bromopyrrole alkaloid possessing a cyclopentane ring fused to an amino imidazole ring and nagelamide K (4) is a unique dimeric bromopyrrole alkaloid containing an ester linkage. Nagelamide J (3) exhibited antimicrobial activity against Staphylococcus aureus (MIC, 8.35μg/ml) and antifungal activity against Cryptococcus neoformans (MIC, 16.7μg/ml), while nagelamide K (4) exhibited antimicrobial activity against Micrococcus luteus (MIC, 16.7μg/ml).