The generation of highly reactive oxygen (O-1(2)) is very significant for a variety of applications such as degradation, bleaching, chemical synthesis, photodynamic therapy for tumor treatment, and others. Herein, we report a novel peroxide-dianion-embedded bimetallic macrocycle, [O-2(2-)@Ag4Cu4L4](2+) (2), that can completely release the inserted peroxide dianion as the singlet oxygen (O-1(2)) via a H+-assisted disproportionation process in methanol. Notably, the resulting empty Ag4Cu4L4(ClO4)(4) (3) is able to trap oxygen (O-2) from air and fixes it in the macrocycle host as a peroxide dianion; furthermore, it releases it as O-2 again in the presence of H. So, the bimetallic macrocycle [Ag4Cu4L4](4+) herein behaves as a highly efficient reusable triplet oxygen receptor and singlet oxygen generator.