Non-covalent interactions between of {N,N'-bis[(2-pyridinyl)methylene]-1,2-benzenediamine]-bis (nitrato)} Cu(II) with pyridoxine hydrochloride in methanol were investigated by a combination of physico- chemical and spectrophotometric methods at T = (298.15, 308.15 and 318.15) K under ambient pressure. From measured density and viscosity data the apparent molar volume (phi(V)), the slope (S-V), standard partial molar volume (phi(0)(V)), standard transfer volume (Delta(t)phi(0)(V)), isobaric apparent molar expansibility (phi(E)), standard isobaric partial molar expansibility (phi(0)(E)), the viscosity B-coefficient, its temperature derivative (partial derivative B/partial derivative T), solvation number (S-n) were calculated and discussed on the basis of specific or non-specific (solute + cosolute) and (solute + solvent) interactions. Thermodynamics of viscous flow were discussed on the basis of the transition state theory. Spectrophotometric results indicated 1:1 (solute + cosolute) interaction between the complex and pyridoxine hydrochloride. (C) 2014 Elsevier Ltd. All rights reserved.