In the present paper, we report the optical properties of the bicolor composite phosphor on the base of CaS and Ga2S3 and study the possibility using this composite to obtain a white light LED. In particular, the energy transfer between the green and red emission bands of the bicolor composite phosphor activated by Eu2+ ions was studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)