Toward improvement in the reliability of polymeric materials, it is necessary to develop technologies that prevent and report fractures in materials caused by an external force. Among some strategies to dramatically improve the mechanical performances of unfilled polymer networks, an energy dissipation mechanism via rupture of weak bonds, socalled sacrificial bonds, is one of the promising approaches for realizing tough materials. Furthermore, the burgeoning of polymer mechanochemistry, based on mechano-responsive molecular units, i.e., mechanophores, enables detection, or sometimes utilization, of molecular scale force within a polymer. This review briefly summarizes the two research fields and points out their remaining issues. In the context of the current situation, our recent achievement on a toughened and self-reporting elastomer emerging from the fusion of the sacrificial bond principle and polymer mechanochemistry is discussed.