This study utilized density functional theory (DFT) simulations to investigate the adsorption behavior and sensing capabilities of pristine penta-B₂C and penta-graphene monolayers toward volatile amines namely methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) which are crucial compounds of fish spoilage. The results reveal that both monolayers exhibit favorable adsorption energies, with penta-B₂C showing notably stronger interactions than penta-graphene, making it suitable for both detection and removal applications. While adsorption significantly modulates the band gap of penta-graphene, penta-B₂C displays milder electronic responses, underscoring their distinct sensing mechanisms. Both materials demonstrate φ-type sensor behavior and exhibit enhanced conductivity with reduced resistance upon amine adsorption, as confined by current–voltage (I–V) analyses. Based on the results of current sensitivity, penta-graphene and penta-B₂C exhibit the highest sensitivity toward MA and TMA, respectively. These findings highlight the potential of pristine pentaB ₂C and penta-graphene as efficient nanostructures for the detection and removal of spoilage-related amines, offering promising avenues for freshness monitoring in the seafood industry