The present invention relates to a method for forming a nanocomposite having a core-shell structure, the method comprising the steps of: forming a core comprising a first fluorophore capable of aggregation induced emission, and depositing a second fluorophore capable of aggregation caused quenching onto the surface of the core to form a shell at least partially surrounding the core. The present invention also relates to a nanocomposite obtained by said method, and a method of altering the fluorescence of said nanocomposite. The nanocomposite may exhibit dual emission colours and opposite aggregation fluorescent behaviours.