Temperature (T) dependences of the emission spectra and lifetimes of hexarhenium(ill) clusters, [Re-6(mu(3)-S)(8)X-6](4-)(X = Cl-, Br-, and I-) in the crystalline phase were studied in detail. An increase in T from 30 to 70 K resulted in a red-shift of the emission spectrum of the cluster, while an increase in T above 70 K gave rise to a gradual blue-shift of the spectrum. On the other hand, the emission lifetime of the cluster decreased sharply from 30-40 to 13-20 mu s on going from 30 to 60 K, while that decreased gradually above 60 K: 5-6 mu s at 290 K. Such emission behaviors of [Re-6(mu(3)-S)(8)X-6](4-) were observed irrespective of X. The results were then analyzed by assuming the contributions of the emissions from the lowest-energy excited triplet-state sublevels. The present study demonstrated that the characteristic T dependent emission spectra and lifetimes of [Re-6(mu(3)-S)(8)X-6](4-) were explained reasonably by a single context of the contributions of the emissions from four excited triplet-state sublevels,