Innovations in polymer mechanochemistry has created new tools for designing stress responsive materials by harnessing macroscopic mechanical force at the molecular level. Through introducing mechanochemically active functional groups (“mechanophores”), a new generation of stress-sensing or stress-responsive materials can be developed. For example, a force-induced colormetric/luminescent response would allow in-situ visualization of stress distribution in the bulk materials. However,current challenges include the need to expand the force range achieved in bulk elastomers by designing mechanophores with various activation threshold forces. Herein, the challenges are being addressed through (A) the design of a spirodihydroindolizine (DHI) mechanophore that is mechanochromic and activates in the high force regime (B) the design of a coumarin dimer mechanophore which yields highly fluorescent coumarin monomer after being activated and its potential application as force probes in filled elastomers.