Abstract: The luminescent platinum 1,2-enedithiolates are dual emitters with a short-lived 1ILCT* singlet and long-lived oxygen-sensing 3ILCT* triplet (ILCT; intraligand charge transfer transition) emissive excited states. Since only the triplet is quenched by molecular oxygen, the singlet serves as an internal standard for dioxygen measurements. This allows the concentration of dioxygen to be determined from the ratio of the singlet/triplet emissions. The novel dual emitters are readily polymer encapsulated to allow measurement of dioxygen in a range of settings. These polymer encapsulated dual emitters will serve as a drop-in step-out replacement sensor for currently available dioxygen measuring devices.