Photoinduced linkage isomers (PLIs) of the nitro-ligand were generated and comprehensively characterized in a square planar unit [Pd(NH 3) 3 NO 2 ] + of the complex salts [Pd(NH 3) 4 ][Pd(NH 3) 3 NO 2 ][MOx 3 ]⋅yH 2 O (M = Cr (Cr), Rh (Rh), Co (Co), Ox = oxalate). The structural (XRD) and spectroscopic (IR, UV-vis) investigations at 10 and 150 K allowed to determine the structures of several photoinduced linkage isomers, endo-ONO (PLI1, 2) and exo-ONO (PLI3, 4) isomers generated by irradiation with 365 nm from the initial NO 2 (GS), along with the assignment of the IR-bands to each structural isomer. Based on a combination of these methods the photo-and thermally induced interplay of PLIs was investigated. Irradiation in the temperature range 10-80 K induces the formation of both endo-and exo-ONO isomers, while increasing the temperature up to 150 K results in the formation of only endo-ONO isomers. The structural arrangement of the endo-ONO and exo-ONO PLI is strongly influenced by intermolecular interactions due the partial occupation of a neighboring site by water molecules. The investigation of thermal dynamics of PLIs revealed that the thermal decay of the exo-ONO isomer occurs via two steps exo-ONO→endo-ONO→NO 2. The kinetic parameters (E a , k 0) of both decay processes were determined together with the characteristic decay temperatures (T d) by IR-spectroscopy. According to the photoinduced dynamics measured by IR-spectroscopy, the mechanism of PLIs formation in [Pd(NH 3) 3 NO 2 ] + could be described as NO 2 →endo-ONO→exo-ONO.