Experimental data for Henry's law constant of organic solutes at temperatures between (313.15 and 363.15) K are unavailable or scarce. A method is presented to measure Henry's law constant of organic solutes in water at these temperatures known as extended Equilibrium Partitioning in Closed Systems (extended EPICS). Extended EPICS rely upon liquid concentration sampling rather than the gas-phase headspace analyses required by the basic EPICS method. The results for four selected organic chemicals (benzene, methylbenzenc, chlorobenzene, and bromobenzene) agree well with values calculated from literature solute vapor pressure and solubility data and from correlations.