Three members of the family of trigonal bipyramidal (TBP) complexes of general formula [M(tmphen)(2)](3)-[M'(CN)(6)](2) (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) or [M3M'(2)], which are known to exhibit thermally induced spin crossover and charge transfer, have been investigated for optical and photomagnetic properties. The light-induced excited spin-state trapping (LIESST) effect found in classical spin crossover compounds, such as [Fe(phen)(2)(NCS)(2)], was explored for the [Fe3Fe2] and [Fe3Co2] compounds. Similarly, inspired by the light-induced charge-transfer properties of K0.2Co1.4[Fe(CN)(6)] center dot 6.9H(2)O and related Prussian blue materials, the possibility of photo-induced magnetic changes was investigated for the [Co3Fe2] TB]? complex. Optical reflectivity and magnetic susceptibility measurements were used to evaluate the photoactivity of these compounds. A comparison of these data before and after light irradiation demonstrates that (i) the spin, crossover of the Fe-II centers in the [Fe3Fe2] and [Fe3Co2] analogues and the (ii) charge transfer events in the [Co3Fe2] complex I occur with temperature and irradiation. In addition, photomagnetic behavior is exhibited by all three compounds. The photo-, conversion efficiency has been estimated at 20% of photo-induced high spin Fe-II centers in [Fe3Co2], 30% of paramagnetic Co-II-Fe-III pairs in [Co3Fe2], and less than 2% of photo-induced high spin Fe-II centers in [Fe3Fe2].