The optical absorption and photoluminescence spectra of undoped and cobalt doped Cd4GeSe6 single crystals are presented. The Cd4GeSe6:Co2+ absorption spectrum was analysed in terms of Co2+ ion Td site along with the spin-orbit coupling effects. Two donor and two acceptor levels were identified along with multiphonon processes in photoluminescence study of Cd4GeSe6.