The deep blue color of azulene is drastically changed by the addition of substituents such as CH[subscript 3], F, or CHO. Computational semiempirical methods using ZINDO CI are used to model azulene and azulene derivatives and to calculate their UV-vis spectra. The calculated spectra are used to show the trends in absorption band shifts upon addition of electron-donating or electron-withdrawing groups at various carbon positions in azulene. The shifts of the absorption peaks may be predicted using the shapes of the HOMO, LUMO, and LUMO+1 of azulene, a non-alternant hydrocarbon. The predicted shifts of the absorption peaks are compared with those calculated by ZINDO CI. (Contains 4 figures and 1 table.)