This study describes the synthesis and characterization of the photoluminescent and water‐soluble complex cis‐[Ru(phen)2(2Apy)]2+ (Ru2Apy, phen=1,10‐phenanthroline and 2Apy=2‐aminopyridine), which exhibits spectroscopic and physicochemical properties favorable for biological applications. 1H‐NMR, photoluminescence, and UV‐vis spectroscopy experiments show bidentate coordination of the 2Apy ligand, which leads to a blue shift in the emission spectrum and places the 3MLCT in proximity to the 3MC excited states, thus enabling a photochemical pathway. Under continuous light irradiation at 450 nm, Ru2Apy opens the coordinating site of the NH2 group in 2Apy to form the monoacetonitrile complex cis‐[Ru(phen)2(2Apy)(CH3CN))2+, with a quantum yield of 0.457. Further irradiation leads to a second photoprocess to form the bis‐acetonitrile cis‐[Ru(phen)2(CH3CN)2]2+ complex, with a quantum yield of 0.002. Ru2Apy binds to human serum albumin via non‐covalent interactions with Kb=4.63×10−9 mol L−1, ΔH=−3.4×10−3 kcal mol−1, and ΔS=8.7 kcal mol−1K−1, and displays a moderate inhibition of AChE with an IC50 of 13.2±2.0 μmol L−1. The complex also exhibited high uptake into HeLa cells with no cytotoxicity. Furthermore, the emissive response of Ru2Apy was be used to assess, in real‐time, the aggregation of Aβ1–40 in a dose‐dependent manner.