Embracing strategies that circumvent the complexities and disordered structures of electrochemiluminescence (ECL) emitters to improve charge transfer efficiency is crucial for advancing ECL technology to the forefront. Here, heteroatom-involved cocrystal engineering was introduced, constructing an ECL system with controllability of the charge transfer process. Through the mutual recognition and coassembly between functional monomers, highly ordered cocrystal superstructures are formed. The layered donor-acceptor arrays in cocrystals accelerated charge transfer, producing a remarkable ECL performance. Furthermore, distinct heteroatoms possess the capability to modulate the charge distribution of monomers by either pushing or pulling electrons. This modulation ultimately affects the charge transfer pathways within cocrystals, enabling ECL emissions of varying intensities and wavelengths. Notably, the presence of UO22+ would significantly inhibit the charge transfer in cocrystals, causing a quenching of ECL signal. This unique characteristic enables precise and selective detection of UO22+. The heteroatom-involved cocrystals hold immense potential to construct next-generation ECL emitters and create fresh opportunities for the advancement of ECL technology.