Solubilities are reported for 2,6-diaminopyridine dissolved at atmospheric pressure in toluene, o-xylene, and ethylbenzene from (273.25 to 361.25) K, methanol, ethanol, and 2-propanol between (266.15 and 321.25) K, and sodium hydroxide solution containing mass fraction of 0.000 % to 17.308 % sodium hydroxide over the temperature range of (273.55 to 326.35) K. Results of these measurements are fitted with the combined binary solvent Margules equation. For the systems studied, the Margules equation is found to provide very reasonable mathematical representation, with average deviations between experimental values and calculated ones being on the order of +/- 2.2 % or less. The coupler parameters of the Margules equation (A(21), A(12)) and the enthalpy of fusion (Delta H-fus) of 2,6-diaminopyridine in different systems are obtained by regressing the experimental data.