A new series of perylene and hemicoronene diimides, obtained by visible light photocyclization, are presented, between them some remarkable examples that are soluble in only water, and give nanoparticles by self-association. Those compounds work as new fluorescent materials in water by complexation with cucurbit[7]uril, as well as selective G-quadruplex binding ligands with remarkable cytotoxic activity when the interaction with G4 was sufficiently strong. [Display omitted] • New hemicoronenediimides obtained by photocyclization of perylenediimides are presented. • The water-soluble compounds 5 and 6 form nanoparticles by self-association. • Disaggregation by interaction with cucurbit[7]uril turn-on the emission of 5 and 6. • 5 and 6 are selective G-quadruplex binders, being 5 the most sensitive probe. • 5 is a high cytotoxic compound towards lung adenocarcinoma cells. [ABSTRACT FROM AUTHOR]