The scientific article titled "Two-photon absorption properties of fluorescent proteins," published in the prestigious journal Nature Methods, serves as a critical digital resource for researchers employing two-photon excitation in biological imaging. This publication provides a comprehensive review and systematic characterization of the two-photon absorption (2PA) properties of a diverse array of fluorescent proteins. The article is designed to guide researchers in selecting the most suitable and brightest fluorescent proteins, along with their optimal excitation wavelengths, for various two-photon microscopy applications. It covers both established and newer variants, including far-red fluorescent proteins, offering a valuable comparative analysis of their photophysical characteristics. It delves into the significant advantages of two-photon laser scanning microscopy (2PLSM), such as its ability to reduce out-of-focus photobleaching, minimize autofluorescence, achieve deeper tissue penetration, and provide intrinsically high three-dimensional resolution. These benefits make 2PLSM an exceptionally powerful tool for studying complex biological systems, particularly in living organisms. By presenting detailed data on 2PA spectra and cross-section values, the publication enables researchers to make informed decisions regarding experimental design and optimization. It is an essential reference for anyone involved in advanced microscopy, bioimaging, and the development of new fluorescent probes for cutting-edge biological research.