For lump and nano-cobalt sulphate (CoSO4) in pure water, the affiliation and thermodynamic association characteristics were measured at 298.15, 303.15, 308.15, and 313.15K. based on the bulk and nano CoSO4 molar conductance, Estimates were made for the parameters of the solvation, such as the activity coefficient, free energy of association, enthalpy of association, association constant and entropy of association. We talked about each of these solvation parameters. From the interaction of bulk and nano CoSO4.7H2O with fuchsin acid, there were two stoichiometric complexes produced. 1:1 and 1:2 In the case of 1:1 (CoSO4.7H2O/fuchsin acid) compared to 1:2 (fuchsin acid in pure water as solvent), the complex Kf and ∆Gf are higher, indicating simpler complex formation. Temperature increase resulted in a drop in the formation constants. The complexation's negative ∆Gf values demonstrate that the process of complex synthesis was spontaneous and that the temperature improved the spontaneity.