824-829Binding of a binaphthoquinone derivative namely, 5a,5b-dimethyldibenzo[b,h]biphenylene-5,6,11,12(5aH,5bH,11aH,11bH)-tetraone (L, C22H16O4) with bovine serum albumin (BSA) and human serum albumin (HSA) have been examined by using fluorescence spectroscopy. The fluorescence emission of the L is quenched upon addition of L to a solution of BSA or that of HSA, but the BSA has shown a higher affinity towards L over the HSA protein. A molecular docking study is also performed to suggest the sites of BSA for weak interactions to bind the L. The docking analysis, has revealed the N-H•••O hydrogen bonds of L with different amino acid residues. The L is located at about 7.7Å away from the Trp-213 which is the fluorescent unit of the BSA suggesting the role of environment of the tryptophan residue to be an important to have changed the emission intensities