Photophysical and photochemical properties of a series of Ru(II) complexes containing substituted 1,2,4-triazole ligands have been investigated. Photostability has been observed for a number of complexes containing triazoles. The photoreactivity for these complexes can be induced or inhibited by protonation or deprotonation of the triazole ring; Photoinduced linkage isomerism has been observed for the two isomers of [Ru(bpy)2(Hptr)]2+ (bpy = 2,21-bipyridine; Hptr = 3-(pyridin-2-yl)-1,2,4-triazole). For Ru(bpy)2 complexes containing pyrazyltriazole ligands, it is found that the nature of the emitting 3m l CT state can be controlled by pH: when the triazole ring is changed from the protonated form to the deprotonated form, the LUMO is switched from bpy to pyrazyltriazoles. The emission lifetime for the two isomers of [Ru(phen)2(ptr)]+ (phen = 1 ,1 0 -phenanthroline) is found to be much longer than their bpy- or dmb-based (dmb = 4,41-dimethyl-2 ,2 1-bipyridine) analogues and comparable to [Ru(bpy)3]2+. These phen-based two isomers are photostable. Significant oxygen quenching behaviour has been observed for these two isomers. Ru(II) complexes containing a pyridyltriazole ligand linked to a hydroquinone group have been synthesised and separated using semi-preparative HPLC. The compounds have been characterised using ^H-NMR, UV-vis absorption, emission and electrochemistry. Preliminary photophysical studies show that for one of the coordination isomers, reductive quenching of the 3mlCT state by the hydroquinone group is at best inefficient. For another isomer’, where the hydroquinone group is coordinated, protonation results in an increase in emission lifetime, of which the value is much higher compared to the first isomer, where the hydroquinone is uncoordinated, and also longer compared to the corresponding dinuclear complex. Electrochemically induced proton transfer process has been observed for two Ru(II) complexes containing triazole ligands, where no external proton source is needed and the process can be most likely viewed as intramolecular.