A series of mechanoluminescent polyurethane/siloxane hybrid polymers are synthesized through mild polycondensation and solâgel hydrolysis process with 1,2âdioxetane as the mechanophore. With joint advantages of polyurethanes and siliconâcontaining polymers, these hybrid polymers exhibit good mechanical strength, high elasticity, and water resistance properties. Herein, 1,2âdioxetane acts as an autoluminescent probe of chain scission, which could emit visible and sensitive signals of the covalent bond breaking in these hybrid polymers under mechanical force. Thus, chain scission and chain slipping events during the failure process of these polymers can be effectively discriminated. The current work will offer exciting opportunities to study the failure process of hybrid polymers with unprecedented temporal and spatial resolutions.