Hypoxia, defined as a local insufficiency in the oxygen level, is one of the typical phenomena found in spinal cord injury and solid tumors. Deficiency in the oxygen offers a reductive environment and results in the conversion of nitro groups to amino groups, which can be utilized in the initiation of stimuli-sensitive cascade reactions. A novel hypoxia-sensitive material was synthesized as composed of a hypoxia-activatable trigger unit and two pyrene dyes bound via carbamate linkers, and it produced fluorescence and ultrasound signals. The material was successfully produced through seven synthetic steps and characterized via 1H-NMR and UV-vis absorption analysis. The material maintained its chemical structure at the normoxic state, but underwent degradation into free pyrene dyes, activated trigger units, and carbon dioxides by cascade reactions under the reductive hypoxic condition. Accompanied by the material decomposition, remarkably rapid recovery of the quenched fluorescence was observed within 3 min, and its intensity was completely saturated after 15 min. Notably, the fluorescence intensity from the degraded material was 9.2-fold stronger than that from the same concentration of native pyrene dyes because both the activated trigger unit and free pyrene exhibited bright fluorescence emission. Moreover, the carbon dioxide generated during the degradation of the material formed nanobubbles in the media, increasing the ultrasound contrast by 1.2-fold over the background. In summary, the synthesized material was found to produce a potent, hypoxia-sensitive system to visualize the hypoxic condition in terms of fluorescence and ultrasound responses.