Trisulfide unit is widely found in natural products and has garnered attention due to the unique pharmacological and physiochemical properties. However, despite limited progress, widely applicable approaches for constructing unsymmetrical trisulfides have so far remain scarce. In this work, an easy‐to‐prepare, solid‐state and scalable reagent, S‐substituted sulphenylthiosulphate, has been developed for the divergent synthesis of unsymmetrical trisulfides. Alkyl electrophile substrates, including bromides, chlorides, iodides and tosylates, with diverse substituents are smoothly converted to the corresponding trisulfides with S‐substituted sulphenylthiosulphates and thiourea as another sulfur source. Furthermore, the late‐stage modification of drug molecules was successfully achieved through this method.