Abstract A bottom-modified (4-position) naphthalimide derivative 1 with 1, 8-naphthyridine as binding site has been designed and synthesized. Compound 1 is the first 1, 8- naphthyridine-modified naphthalimide-based sensor that can detect selectively with respect to ratiometric fluorescent change and blue shift in organic aqueous solution. The Job's plot and FAB mass indicate that 1 formed a 1: 1 complex with. A top-modified naphthalimide ...