Infrared and far infrared polarized reflectance spectra of beta -(BEDT-TTF)//2X (X equals I//2Br** minus , AuI** minus //2) are presented. Both have the strongest metallic character along the stacking axis, but two-dimensional plasmon behavior is found at low temperatures in all the materials. The distribution of oscillator strength is discussed with special emphasis on the non-Drude features.