In this paper, the results of the synthesis, structural, vibrational and optical characterization of the CuInSSe pseudo-quaternary compound (CISS) obtained via the assistance of microwave radiation and the conventional ceramic method are compared. The synthesis was performed in vacuum sealed quartz ampoules and exposed to microwave radiation at 2, 3 and 4 minutes for 3 days. The structural characterization indicates that the products are single phases with crystal structure Chalcopyrite-type. The average particle sizes were estimated through the use of Scherrer's formula, and the results showed that there is a correlation between the duration of exposure to radiation and the particle size obtained. The SEM-EDS analysis confirms the chemical compositions expected. The Raman analysis confirmed the formation of the pseudo-quaternary phase presenting the characteristic peaks and displacement for these compounds. Finally, the measurement of diffuse reflectance show band-gap values E-g between 1.21 and 1.29 eV allowing us to conclude that the microwave-assisted synthesis leads to the obtaining of the CISS phase, which are presented as good candidates to be used as absorbing material in solar cells.