Visible pump−probe spectroscopy has been used to identify and characterize short-lived metal-to-metal charge transfer (MMCT) excited states in a group of cyano-bridged mixed-valence complexes of the formula [LCo^IIINCM^II(CN)₅]^-, where L is a pentadentate macrocyclic pentaamine (L¹⁴) or triamine-dithiaether (L^14S) and M is Fe or Ru. Nanosecond pump−probe spectroscopy on frozen solutions of [L¹⁴Co^IIINCFe^II(CN)₅]^- and [L^14SCo^IIINCFe^II(CN)₅]^- at 11 K enabled the construction of difference transient absorption spectra that featured a rise in absorbance in the region of 350−400 nm consistent with the generation of the ferricyanide chromophore of the photoexcited complex. The MMCT excited state of the Ru analogue [L¹⁴Co^IIINCRu^II(CN)₅]^- was too short-lived to allow its detection. Femtosecond pump−probe spectroscopy on aqueous solutions of [L¹⁴Co^IIINCFe^II(CN)₅]^- and [L^14SCo^IIINCFe^II(CN)₅]^- at room temperature enabled the lifetimes of their Co^II−Fe^III MMCT excited states to be determined as 0.8 and 1.3 ps, respectively.