The discovery and designed synthesis of multifunctional materials is a leading pursuit in materials science. Herein, we report a novel hydro-isocyanurate, N 2 H 4 Zn(HC 3 N 3 O 3 ), which combines strong second harmonic generation (SHG) and ultra-long room-temperature phosphorescence (RTP). The SHG intensity is the highest within the cyanurate system (13 × KDP), and RTP lifetime extends up to 448 ms, accompanied by a long-lasting afterglow visible to the naked eye for 1.2 s, surpassing most of the current metal-organic complexes. This advancement holds promise for the development of multifunctional optoelectronic devices, particularly leveraging second-harmonic generation (SHG) processes.