Zeise’s salt, [PtCl3(H2C=CH2)], is the oldest known organometallic complex, featuring ethylene strongly bound to a platinum salt. Many derivatives are known, but none involving dinitrogen, and indeed dinitrogen complexes are unknown for both platinum and palladium. Electrospray ionization mass spectrometry of K2[PtCl4] solutions generate strong ions corresponding to [PtCl3(N2)], whose identity was confirmed through ion mobility spectroscopy and MS/MS experiments that proved it to be distinct from its isobaric counterparts [PtCl3(C2H4)] and [PtCl3(CO)]. Computational analysis established a gas-phase platinum-dinitrogen bond strength of 116 kJ mol-1, substantially weaker than the ethylene and carbon monoxide analogues but stronger than for polar solvents such as water, methanol and dimethylformamide, and strong enough that the calculated N-N bond length of 1.119 Å represents weakening to a degree typical of isolated dinitrogen complexes.