Abstract Starting from the previously developed P-gp ligands 1a and 1b (EC 50= 0.25 μM and 0.65 μM, respectively), new arylmethyloxyphenyl derivatives have been synthesized as P-gp modulators in order to investigate:(i) the effect of small electron-donor groups (OMe)(5– 11),(ii) the effect of the replacement of methoxy groups with an electron-withdrawal substituent (Cl) on C-ring (13)(iii) the effect induced by the replacement of C-ring with ...