Time- and space‐resolved luminescence studies of anthracene crystals have revealed efficient radiative energy transfer by polaritons over macroscopic distances at very low velocities (V<10−3c). Diffusive and ballistic propagation regimes of (quasi)waveguide polarions modes can be differentiated. Spatial distribution of luminescence intensity reflects the crystal (and defect) symmetry. Anthracene microcrystals may be useful as media for optical signal transfer in molecular structures.