<p>Similarly to coordination compounds, metal nanoparticles can exhibit labile or inert character concerning the ligands' substitution behavior, as exemplified by the Turkevich AuNP@citrate (labile) and the gold ranelate AuNP@ran (inert) nanoparticles. The latter are unusual because they encompass a multifunctional thiophene ligand that binds to gold nanoparticles through Au-C bonds. This differential aspect is responsible for their inert character. In this work, two molecular probes, [Ru(bipy)₃]²⁺ and [Ru(bipy)₂DAD]²⁺, have been employed to compare the SERS response of the labile and inert Turkevich and gold ranelate nanoparticles, respectively. In this comparison, it is essential to note that the Ru(bipy)₃]²⁺ probe has no external binding atom since all the bipyridine (bipy) N-atoms are coordinated to the metal center. Therefore, it can only interact with the Turkevich nanoparticles through electrostatic forces. A plasmonic coupling band was observed at around 620&#xa0;nm, showing a significant SERS response, which can only be ascribed to the electromagnetic mechanism. On the other hand, DAD or 4,5-diamine-2,6-dimercaptopyrimidine, exhibits several thiol and diazo groups capable of binding metal atoms. The [Ru(bipy)₂DAD]²⁺&#xa0;probe binds covalently to the Turkevich nanoparticles through the S atoms, inducing a plasmon coupling band around 650&#xa0;nm and a strong SERS response compatible with the chemical mechanism. However, no plasmonic coupling band or SERS effect was observed when the inert AuNP@ran species replaced the labile Turkevich nanoparticles. Therefore, lability should be relevant for allowing electronic contact between the interacting species, contributing to the light scattering mechanism observed in plasmonics and SERS.</p>