Temperature dependence of the light yield of 1-methylnaphthalene based scintillators emitting in the green spectral range was studied in the liquid and frozen states. The light yield of the scintillator frozen at -120 degrees C in vacuum increased 2.2-3.3 times compared to the room-temperature value in air, and reached 88-118% of the level for anthracene. All scintillators cooled to -120 degrees C, and then heated to 20 degrees C exhibited a hysteresis in the temperature variation of the light yield. The duration of signals from the frozen samples in air was somewhat longer compared to that at room temperature. The light yield of scintillators studied was sensitive to the ionization density
