Three novel naphthalimide-based gelators (NAPP, NAMP and NAOP) linked three different amines: 4-(aminomethyl)pyridine, 3-(aminomethyl)pyridine, or 2-(aminomethyl)pyridine were designed and synthesized. NAPP, NAMP and NAOP could self-assemble into fluorescent gels in some solvents and formed a variety of morphologies. The self-assembly behaviors of three gelators in DMSO/H2O (10/1, v/v) were characterized by UV–vis absorption, fluorescence, Fourier transform infrared (FTIR), X-ray diffractions (XRD) and water contact angle experiment, and the effect of different N sites in pyridine in this self-assembly system was investigated. On the base of coordination ability of pyridine groups to metal ions, the self-assembly process could be regulated by the addition of metal ions. NAPP, NAMP and NAOP solutions had highly selective and ultrafast fluorescence detection capabilities for Fe3+ with a low limit of detection. The self-assembly structure and surface wettability of the gel self-assembly system could be adjusted by adding metal ions. The hydrophobic surface of xerogels NAPP and NAMP is transformed into a hydrophilic surface at the present of Fe3+. And the hydrophilic and hydrophobic surfaces of NAPP and NAMP could realize the transformation of hydrophilic and hydrophobic surfaces by the coordination of metal ions. This study provided a way for regulating the self-assembly process by the distance between the N site on pyridine and the amide segment and metal coordination.