A quantum-chemical investigation on the structural and optoelectronic properties of two materials based on carbazole is carried out.The purpose is to display the effect of grafting the fluorine atoms on their optoelectronic and physico-chemical properties.In addition to solubility in the polar solvents and the modification in geometric parameters,the substitution of fluorine destabilizes the HOMO and LUMO levels,decreases the band gap energy and raises conjugation length.These properties suggest the substituted fluorine compound as a good candidate for optoelectronic applications. A quantum-chemical investigation on the structural and optoelectronic properties of two materials based on carbazole is carried out. The purpose is to display the effect of grafting the fluorine atoms on their optoelectronic and physico-chemical properties. In addition to solubility in the polar solvents and the modification in geometric parameters, the substitution of fluorine destabilizes the HOMO and LUMO levels, decreases the band gap energy and raises conjugation length. These properties suggest the substituted fluorine compound as a good candidate for optoelectronic applications.