This chapter discusses how polymer-based chemosensors convert hydrostatic pressure into optical signals. Decorating polymer backbones with emissive units creates ensembles in which chromophore spacing, chain conformation, and local solvation all contribute to the response. Hydrostatic pressure modulates intra- and interchain distances, reorganizes weak interactions, and alters free volumes around the emitters, thereby redistributing the balance among monomer-like, aggregate-like, and excimer-like emission channels in a predictable manner. In some designs, pressure controls competition between nonradiative decay and the formation of emissive species, enabling dual emission that can be read out ratiometrically. In others, conformational adjustment of the polymer scaffold under pressure reversibly shifts the population of emissive states, allowing quantitative, reversible pressure sensing even in viscous or buffered media. Time-resolved and chiroptical measurements clarify the underlying excited-state manifolds and reveal how chain flexibility, chromophore density, and steric configuration determine the form and dynamic range of the pressure response. Together, these results establish general design rules for mechanoresponsive polymer chemosensors, in which volumetric compression is translated into robust ratiometric and chiral optical outputs that are suitable for solution-phase mechanosensing and mechanobiological interrogation.