The colors, wave length maxima, absorptivities, concentration limits, dilution factors, spectral detection limits, Beer's law ranges, color stabilities and interferences of 12 diverse methods for the determination of azulene are compared. Eleven of these methods are new. The molar absorptivities of the different methods range from 17,000 to 110,000. All methods have a concentration limit more sensitive than 1 ppm of azulene; all methods can detect less than a microgram of azulene. For all procedures the structure of the final chromogen has been deduced.