A temperature-dependent photoluminescence study is. reported for single crystals of M[Au(CN)(2)](3) and M[Ag(CN)(2)](3) (M = Tb; Gd; Y). The results indicate that in both Tb[Au(CN)(2)](3) and Tb[Ag(CN)(2)](3) exclusive excitation of the donor leads to sensitized luminescence for the acceptor, characteristic of the D-5(4) --> F-7(J) (J = 0-6) transition of Tb(III). However, the sensitized luminescence is much stronger in Tb[Ag(CN)(2)](3) than in Tb[Au(CN)(2)](3) due to a larger spectral overlap between the [Ag(CN)(2)(-)] emission and the Tb(III) absorption. Upon increasing the temperature, energy transfer is enhanced in Tb[Ag(CN)(2)](3) but inhibited in Tb[Au(CN)(2)](3). In Tb[Ag(CN)(2)](3), a large spectral overlap exists between the [Ag(CN)(2)(-)] donor emission and the Tb(III) acceptor absorption at all temperatures. The Tb(III) sensitized emission is strong at all temperatures and is enhanced upon a temperature increase while the [Ag(CN)(2)(-)] emission is quenched. An activation energy of 53.7 cm(-1) (+/-2.5 cm(-1)) has been calculated for the energy transfer process in Tb[Ag(CN)(2)](3) In Tb[Au(CN)(2)](3), the Tb(III) sensitized luminescence decreases upon increasing the temperature. The [Au(CN)(2)(-)] emission is strong and does not undergo a complete quenching as the temperature increases toward room temperature. The [Au(CN)(2)(-)] emission undergoes a red shift upon cooling, which leads to an increased spectral overlap with-the D-5(4) --> F-7(6) absorption band of Tb(III); thus energy transfer is tuned by controlling the temperature. The sensitized luminescence intensity of Tb(III) in Tb[Au(CN)(2)](3) is directly proportional to the numerical value of the donor-acceptor spectral overlap, in agreement with the theory of radiationless energy transfer.