Photothermal therapy （PTT） has become a novel minimally invasive cancer treatment due to its potential for high inherent specificity

non-invasiveness

and low damage. It mainly uses photothermal agents （PTAs） or photosensitizers （PSs） to convert light energy into heat energy under light conditions to induce cancer cell apoptosis. PTAs are one of the key factors that determine the effect of photothermal therapy. Squaraine dyes are a class of conjugated organic molecules formed by the condensation of two electron-rich units and one electron-withdrawing squaric acid core unit

exhibiting a resonance-stabilized zwitterionic structure. Squaraine dyes possess strong absorption and emission properties in the visible and near-infrared regions

with a molar extinction coefficient (ε) as high as 105 L/mol·cm. Additionally

Squaraine dyes have advantages such as easy aggregation

simple synthetic routes

good photothermal stability

and strong structural modification capability. Therefore

squaraine dyes hold great potential as photothermal therapy photosensitizers. This article provided a comprehensive review of the recent research progress in the application of squaraine dyes in tumor photothermal therapy

aiming to serve as a clinical reference.