From structure--anti-L1210 relationships developed earlier for the 4'-(9-acridinylamino)alkanesulfonanilides it was predicted that congeners bearing both lipophilic 3-acridine substituents and compensatory hydrophilic function(s), together providing an overall molecular lipophilic--hydrophilic balance close to optimum, should have augmented antitumor properties. The acceptability of a variety of hydrophilic functions, and optimum positioning of these, has now been investigated. A variety of sterically demanding, hydrophilic functions may be acceptably appended to the acridine 4(5) position suggesting considerable site bulk tolerance. A variant with both a lipophilic 3-acridine substituent (3-iodo) and a hydrophilic 5-(2,3-dihydroxypropoxy) function is markedly more active than previous examples in the early treated, intraperitoneally (ip) dosed, ip implanted L1210 system, the assay system employed in the structure--activity analyses. However, this latter compound, on ip administration, failed to significantly inhibit subcutaneously implanted L1210 whereas earlier variants, under the same conditions, provided significant tumor inhibition. In this drug series the observed order of relative drug effectiveness alters with changing site of tumor implantation.