S1 ‘Supporting Information’ An Experimental and Computational Analysis on the Differential Role of the Positional Isomers of Symmetric Bis 2-(pyridyl)-1H-benzimidazoles as DNA Binding Agents Padmaparna Chaudhuri, Bishwajit Ganguly and Santanu Bhattacharya* Emission behavior in different solvents (Figure S1). S2 Fluorescence titration with [Poly(dG-dC)] 2 (Figure S2) S3 Cartesian coordinates of full-optimized geometry in S4-S9 the gas phase at RHF/6-31G* level. (Table S1-S6). Relative energies for the conformers of o-pyben, m-pyben and p-pyben S10 in gas-phase at RHF/6-31G* level. (Table S7) Cartesian coordinates of full-optimized geometry in the gas and aqueous phases at B3LYP/6-31G* level. (Table S8-S19). S11-S22 Cartesian coordinates of full-optimized geometry in the gas-phase of monoprotonated species S23-S25 at B3LYP/6-31G* level. (Table S20-S22). The natural charge on the pyridine benzimidazole nitrogens in conformations 1 and 2 calculated S26 by NBO analyses at B3LYP/6-31G*. (Table S23) Evolution of the gas-phase and aqueous-phase conformational energy of the pyridine-benzimidazole fragment as a function of the torsional S27 angle α computed at RHF/6-31G* level. (Figure S3) Summary of the potential surface scan at B3LYP/6-31G* level S28-S31 (Table S24-S31). Relative energy for the pyridine-benzimidazole fragment for calculations S32 at B3LYP/6-31G* and RHF/6-31G* levels in gasphase. (Table S32). Relative energy for the pyridine-benzimidazole fragment for calculations S33 at B3LYP/6-31G* and RHF/6-31G* levels in aqueous phase. (Table S33) Solute radii (Table S34) S34