<p>Densities of DMF and corn oil-DMF mixtures were measured, and the effect of potassium iodide (KI) on their density was studied at temperatures of 303.15⁓323.15&#xa0;K and ambient atmospheric pressure of 1&#xa0;atm. The density of the DMF and corn oil-DMF mixtures increased with the addition of corn oil and KI, whereas a decrease in density was observed with the rise in experimental temperature. Apparent molar volume (<i>V</i>_ϕ) of KI solutions was calculated from the densities of solvent and solution. The <i>V</i>_ϕ decreased with the addition of KI, while an increase occurred with the addition of corn oil and temperature rise. Limiting apparent molar volume (<i>V</i><Stack> _ϕ ^o </Stack>) was calculated from Masson’s and Redlich, Rosenfeld, &amp; Meyer’s (RRM) equations and further utilized to evaluate Hepler’s constant; (δ²<i>V</i><Stack> _ϕ ^o </Stack>/δ<i>T</i>²)_<i>P</i>. A negative Hepler’s constant confirmed that KI acts as a structure-breaker in DMF and corn oil-DMF mixtures, and the same was also supported by the trends of thermodynamic parameters.</p> Graphical abstract <p></p>