The assembly of plasmonic nanostructures can induce near-field coupling of surface plasmons, leading to the generation of hot spots that are actively exploited for surface-enhanced Raman scattering (SERS). Arrays of monolayer nanoprisms and heterogeneous bilayer nanoprisms are constructed on the stretchable polydimethylsiloxane (PDMS) substrate, and unique plasmon-coupling-based localized surface plasmon resonance (LSPR) properties are investigated with reproducible and enhanced SERS results upon extension and contraction. It is found that the SERS activity observed from the heterogeneous bilayer nanoprisms is greater than that of monolayer nanoprisms upon the extension and contraction transitions. The advanced flexible plasmonic-couplingbased devices with tunable and quantifiable performance herein suggested are expected to unlock promising potential in practical biosensing, biotechnological applications, and optical devices.