This paper presents an experimental and computational study on implementing a dual cavity slashface cooling scheme on the thermal performance for the first stage nozzle guide vane with an axisymmetric, converging endwall. An upstream dual-row, staggered cylindrical hole cooling scheme provided purged coolant. The study was conducted under representative engine conditions of Maexit = 0.85 and Reexit,Cax = 1.5 × 106. Data were collected and analyzed using infrared thermography to map the endwall heat transfer performance throughout the passage. A flow visualization study was employed to gather qualitative insights into the endwall flow field. In addition, a complimentary computational fluid dynamics study was carried out to understand the endwall flow ingestion and egress behavior near the slashface. Results indicate that the dual-plenum slashface scheme leads to a unique ingestion-egression-ingestion-egression pattern. The ingestion and egression suppress the upstream coolant attachment at mid-passage near the suction side but create a favorable coolant coverage downstream of the slashface tail-end, where the neat heat flux reduction is 0.4–0.5. The study also compared the dual-plenum design with the single-plenum design and concluded that the dual-plenum slashface is superior in film cooling performance.