An unprecedented intrinsic yellow phosphor with high PL quantum efficiency and a unique MOF-like organic-inorganic hybrid open framework has been synthesized under mild thermal conditions; the structure of NTHU-6 is built from small organic oxalate linkers and large inorganic hexameric octahedral Ga-O clusters; its extraordinary yellow emission was suspected to correlate with defects evoked by disorderliness near large pores with the template presumed to act as a sensitizer.