DNA is prone to structural polymorphism: beyond the iconic Watson-Crick double helix, nucleic acids can adopt a number of unusual motifs, at least in vitro. Scientists around the world gather every two years to discuss two of these oddities: G-quadruplexes and i-DNA. The seventh international meeting on G-quadruplex Nucleic Acids was held in Changchun, in Jilin province of the P.R. of China, approx. 1000 km North-east of Beijing. Nearly 320 participants gathered from Asia, Europe, North America and Oceania. More than 80 talks and as many posters summarized our current knowledge of these unusual DNA and RNA structures. During this meeting, the creation of the G4 society was announced, in order to coordinate efforts and share tools and knowledge in our field (https://www.g4-society.org). •Meeting report for the seventh International Meeting on Quadruplex Nucleic Acids, Changchun, China, 6–9 Sept 2019.•Over 300 scientists gathered to share their newest results in the Quadruplex field.•Recurrent themes were: structure and folding, applications to biotechnologies, formation in cells, proteins & ligands.