The present invention relates to phenyl-substituted heterocyclyl derivatives of the formula (I),wherein Z, n, m, R1, R2, R3, R4, R5, R6, R7 and R8 are as described in the description and their use as prostaglandin receptor modulators, most particularly as prostaglandin D2 receptor modulators, in the treatment of various prostaglandin-mediated diseases and disorders, to pharmaceutical compositions containing these compounds and to processes for their preparation.