Light-confining nanoporous anodic alumina optical microcavities (NAA−μCVs) were used as a platform material to selectively detect and identify model volatile organic compounds (VOCs) through their unique adsorption−desorption kinetic fingerprints. The architecture of NAA−μCVs was engineered by sinusoidal pulse anodization to feature resonance bands (RBs) at three specific positions in the visible spectrum. The transmission spectrum of NAA−μCVs featured well-resolved RBs, the average normalized quality factor of which was ∼40. The optical sensitivity of NAA−μCVs upon exposure to gas mixtures of VOCs (e.g., 2propanol, ethanol, and acetone) of varying concentrations was studied by monitoring dynamic spectral shifts in their characteristic RB in real time. NAA−μCVs show unique responses to different VOCs, which also rely on the spectral position at which the NAA−μCV structure recirculates light constructively and the average porosity of the photonic crystal platform. This in turn provides an effective means of detecting and identifying VOCs. A comprehensive characterization of the adsorption and desorption kinetics of VOCs in NAA−μCVs was conducted to elucidate the mechanisms behind these optical responses. A two-stage desorption kinetic model was proposed to describe the desorption process, indicating distinctive desorption rates for adsorbed molecules of specific VOCs. The desorption kinetics can be harnessed as a unique chemical fingerprint that could be used to identify and classify VOC gases based on their desorption behavior. Our findings pave the way for further developments of gas sensors based on NAA photonic crystal structures, which could also have implications across other optical technologies.