A unique one-dimensional ribbon [Cu(bapa)]2[Mo(CN)8]·7H2O (1) (bapa = bis(3-aminopropyl)amine), consisting of {[Cu(bapa)]3[Mo(CN)8]2}2− trigonal bipyramids and {[Cu(bapa)]2[Mo(CN)8]2}4− rhombuses linked through [Cu(bapa)]2+, was obtained and its photomagnetic properties were investigated. After irradiation at selected wavelengths (405 and 532 nm) or with white light, a global increase of the magnetic moment was observed. The initial state of the compound can be fully recovered by heating the sample above the temperature of relaxation of 253 K. This work was completed with photoreversibility studies with red and IR light irradiation which confirm a partial light-induced reversibility of the photomagnetic effect in 1. Finally, the photomagnetic phenomenon in 1 is discussed in accordance with two processes: the spin crossover on Mo(IV) centres and the metal-to-metal charge transfer mechanism in the Cu(II)–Mo(IV) pair.