In this paper, experimental phase equilibrium data for four different binary systems, all composed of methane and a heavy hydrocarbon constituent, are presented. With tetracosane (C24H50), cholestane (C27H48), 1-phenyldodecane (C18H30), and phenanthrene (C14H10) the heavy constituents of the different systems vary significantly in their nature. For the four systems investigated isoplethic measurements were performed covering almost the whole composition range. All systems showed qualitatively the same type of phase behavior, which is characterized through the existence of a solid (pure heavy constituent) - liquid - vapor equilibrium curve, which ends in a so-called second critical endpoint, where the solid phase is in equilibrium with a critical fluid phase. The temperature ranges investigated extend from approximately the triple-point temperature of the heavy component up to 460 K. Only for the system containing 1-phenyldodecane the highest temperatures investigated were 390 K. The pressures applied vary from system to system but did not exceed 400 MPa.