A series of ([(quinolin-2-ylmethoxy)phenyl]sulfanyl}phenyl)acetic acids 2 and S-oxidized derivatives of [(quinolin-2-ylmethoxy)phenyl]sulfanyl}benzoic acids 3 were prepared and their antileukotrienic and antiasthmatic activities evaluated. Regression analysis led to the conclusion that the antileukotrienic activities of compounds 2 correspond to the relationships between these activities and lipophilicity, derived for the previously synthesized series of substituted (arylsulfanyl)benzoic acids 1A, 1B and 1C. Acids 3 are outliers from these relationships, probably due to a somewhat different mechanism of action. A higher antiasthmatic activity was observed in some [(arylsulfanyl)phenyl]acetic acids 2 in comparison with the corresponding analogs bearing the (arylsulfanyl)benzoic acid moiety. The inhibition of 5-lipoxygenase activated protein (FLAP) was determined for these compounds, and the influence of the direct inhibition of LTB4 biosynthesis is discussed to explain the differences in the antiasthmatic effect of the compounds under study.