Metal-organic frameworks (MOFs) exhibit remarkable structural modularity and highly ordered architectures, positioning them as one of the most promising candidates for bridging the gap between organic and inorganic X-ray energy converters. However, efficient emission from the organic linker requires a large π-conjugated system, which often results in a low concentration of heavy atoms and, consequently, poor X-ray absorption and low sensitivity. Conversely, metal-centered emission often relies on rare-earth elements, which are expensive and have narrow emission peaks, reducing the overall light yield. To tackle this challenge, MOFs assembled from small organic linkers that exhibit room-temperature phosphorescence provide an attractive strategy, as these linkers efficiently harvest triplet excitons. Such materials constitute a potent platform for high-performance X-ray energy converters, combining strong X-ray absorption with superior exciton utilization and enhanced radioluminescence.