A mixed culture of two epiphytic fungi from a rotten fruit of mangrove Avicennia marina produced two antibacterial secondary metabolites (A and B). Their structures were elucidated as neoaspergillic acid (A) and kojic acid (B) by comprehensive spectral methods (mainly by 2D NMR spectral methods). The structure of compound B was further characterized by single crystal X-Ray diffraction analysis. The crystal of compound B belongs to monoclinic system

space group is P 2

1

/n. The unit cell parameters are: a=0.378 33 (3) nm

b=1.837 58 (14) nm

c =0.848 89 (7) nm

α=90°

β=96.752 0 (10)°

γ=90°

V=0.586 06 (8) nm 3 and Z=4. Compound A was not obtained when either strains was cultured individually. The results showed that the application of mixed culture technique would be contribute to discover more novel natural products from marine microorganisms.