Advances on chromo-fluorogenic sensing of copper(II) with Schiff bases

[Display omitted] •More than 114 Schiff bases that provide detectable chromogenic and/or fluorogenic to sense Cu2+ were reviewed.•Structure and analytical parameters of the summarized sensors were discussed.•Different sensing mechanisms and applications were discussed.•Future scope on designing of Schiff bases for Cu2+ sensing is discussed. Cu2+ is an important essential trace metal ion and know to play numerous roles in biological systems. The deficiency and excess accumulation of Cu2+ in the human body can cause serious diseases. Therefore, different analytical techniques are developed for the detection of Cu2+ in various environmental, biological and industrial samples. The optical chemosensors based on UV–Vis absorption and fluorescence spectroscopic methods to detect Cu2+ are gaining wide interest due to their low-cost, simplicity, sensitivity and visual response for on-site detection. In designing chemosensors, Schiff bases are extensively explored owing to their facile synthesis, easy structural modification, unique optical and coordinative behaviour. This review compiled more than 114 Schiff bases that can be easily synthesized and provide detectable chromogenic and/or fluorogenic to sense Cu2+. Various analytical parameters, sensing mechanisms, sensing media, structure, chromo-fluorogenic parameters and applications of the summarized sensors are reviewed and discussed.