Five novel 'all-in-one' (AIO) structured cuprous iodide coordination materials 1–5 are presented. With the introduction of planar aromatic groups on the ligand, 1,4-diazabicyclo[2.2.2]octane (DABCO), targeted at eliminating stronger π–π interactions through the twisted nature of the latter species, the complexes displayed good stability, solubility, and high quantum yields of emissions ranging from 70.3–95.3%. Further systematic studies were performed on the relationship between their luminescence and modification of the ligands with halogen atoms. This work provides a reasonable idea for designing luminescent cuprous iodide materials with high quantum yields of emission for use in solid-state lighting in the future. [ABSTRACT FROM AUTHOR]