A semifluorinated isophthalic acid derivative and its mixtures with a number of nonfluorinated analogues have been investigated with scanning tunneling microscopy (STM) at the solution-graphite interface. The specific contrast arising from fluorine atoms in STM images allows us to use this functionality as a probe to aid in the analysis of the data obtained for the mixtures under investigation. Unlike the findings reported for other systems, we did not observe any segregation of fluorinated and nonfluorinated alkyl segments into microdomains that can be attributed to the incompatibility between the two components.