Dear Colleauges, Thank you for the answers (specially ArgousLab was interesting). Does anyone know a program for calculation (estimation) of maximum wavelengths of UV absorption (lambda-max) by using Woodward-Fieser Rules: http://www.chemistry.ccsu.edu/glagovich/teaching/472/uvvis/diene.html Best regards, András Borosy Basilea Pharmaceutica Ltd POB 3255, 65/316 4002 Basel tel: +41-61-6885469 fax: +41-61-6882139 www.basileapharma.com