See:

https://www.researchgate.net/post/UV-Visible_Spectra_Database-can_anyone_help

Hi Emmanuel,

Please look also through these databases:

https://www.internetchemistry.com/chemistry/spectral_database.htm

Marius

Dear Sir Radu and Pelmus, thank you very much.

First, I want to say these data are quite difficult to reach : either the molecule is not available, or the UV-visible spectra.

After an exhaustive research of all the proposed links above (thank you !), in my case, the most appropriate website is the NIST. Having the CAS number is enough to access desired data :

https://webbook.nist.gov/chemistry/cas-ser/