Coordination polymer thin film heterostructures of the Prussian blue analogue Ni-b(II)[Cr-III(CN)(6))(0.7)center dot nH(2)O (NiCr-PBA) and the 3D Hofmann-like spin crossover compound Fe(azpy)[Pt(CN)(4)]center dot xH(2)O {azpy = 4,4'-azopyridine} have been developed, and spin transition properties have been characterized via SQUID magnetometry and Raman spectroscopy. The magnetic response of the ferromagnetic NiCr-PBA layer (T-c approximate to 70 K) can be altered by inducing the LIESST effect (light-induced excited spin state trapping) in the coupled paramagnetic Fe(II) spin crossover material. Whereas an increase in magnetization is measured for the single-phase Fe(azpy)[Pt(CN)(4)]center dot xH(2)O, a decrease in magnetization is observed for the heterostructure. These results indicate the LIESST effect alone cannot account for the sign and magnitude of the magnetization change in the heterostructure, but the temperature profile of the magnetization shows that significant changes in the NiCr-PBA network are correlated to the spin state of the Hofmann-like SCO network.