2016. 57, 8 – UDC 541.6:548.737:541.65 STRUCTURAL CHARACTERIZATION, PHOTOPHYSICAL AND BSA BINDING INTERACTION STUDIES OF 4,4-BIS(BENZIMIDAZOLYL)-2,2-BIPYRIDINE K. Swarnalatha1, P. Rathnamala1, A.A. Babu1, N. Bhuvanesh2 2Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, USA Received September, 02, 2015 1Department of Chemistry, Manonmaniam Sundaranar University, Tirunelveli, Tamil Nadu, India E-mail: swarnalatha@msuniv.ac.in Revised — December, 17, 2015 The title compound is synthesized from the precursors 1,2-diaminobenzene and 2,2-bipyridine-4,4-dicarboxylic acid (dcbpy) and characterized using ESI-Mass, 1H NMR, FT-IR and single crystal X-ray analysis. <...> We are the first to report the crystal structure of the 4,4-bis(benzimidazolyl)-2,2-bipyridine (bimbpy) ligand. <...> The photophysical properties of the compound in dimethyl sulfoxide and in the aqueous medium are studied. <...> The interaction studies of bimbpy with bovine serum albumin (BSA) were performed with the fluorescence technique and it strongly binds with BSA. <...> Benzimidazole containing molecules and their derivatives have been found in biologically active small molecules, such as vitamin B12 and also act as antitumor, antiparasitic, and antimicrobial agents [ 1 ]. <...> The broad spectrum antibiotic nature of the benzimidazole moiety has appealed to researchers to synthesize many benzimidazole and polybenzimidazole type ligands. <...> Because of their unique photophysical properties, these heterocyclic organic molecules have applications in drugs [ 2 ], synthetic fibers [ 3 ], organized assemblies [ 4 ], solar cell [ 5 ], proton exchange membranes in fuel cells [ 6 ], and also in the proton coupled electron transfer processes involved in many biological, catalytic, molecular, and photonic systems [ 7 ]. <...> Many such ligands containing the benzimidazole moiety have already been employed and their transition metal complexes were studied [ 8 ]. <...> We have designed a new 4,4-bis(benzimidazolyl)-2,2-bipyridine ligand which contains two benzimidazole groups tied through the bipyridine moiety. <...> The analogous ligands such as 2,2-bis(benzimidazolyl)-4,4-bipyridine, 6,6-bis(benzimidazolyl)-2,2-bipyridine and their transition metal complexes were already reported [9 ]. <...> Serum albumins are the most abundant protein in plasma <...>