In this chapter, designs of breath analyzer and toxic gas detection sensors are demonstrated by using nanomaterial multilayered structures. This breath analyzer can be used to detect alcohol content in human breath. This breath analyzer contains multiple layers of repeated three dielectric materials and an air groove in between the structure. The breath sample to be tested is passed through the air groove and the light spectrum is observed on the output side. The breath sample without alcohol content will generate a normal light spectrum (treated as a reference spectrum), while, the breath sample with alcohol content will generate a light spectrum different from normal (reference) light spectrum. Thus, alcohol content in the blood can be detected, if we monitor light spectrum. In addition to this, the abovementioned nanomaterial multilayered structure can also be used to detect toxic gas present in the air. The principle of detection is same. This structure generates a light spectrum depending on the material composition, lattice parameters, and gas present in the air groove. First, the light spectrum generated by this structure is recorded for normal air, when there is no toxic gas present in the atmosphere. This spectrum acts as a reference spectrum. After this, if there is a toxic gas leakage anywhere in the surrounding, then this toxic gas will pass through the air groove in the photonic structure and will cause a change in light spectrum. The new light spectrum will be different from the reference light spectrum. So, in this way, the toxic gas present in the atmosphere can also be detected by monitoring the light spectrum of photonic nanomaterial multilayered structure.