The present report describes the synthesis and antiproliferative evaluation of certain 4-anilino-8-methoxy-2-phenylquinoline and 4-anilino-8-hydroxy-2-phenylquinoline derivatives. The antiproliferative activity of 4'-COMe-substituted derivatives decreased in an order of 6-OMe (1, 3.89 microM) > 8-OMe (8, 10.47 microM) > 8-OH (9, 14.45 microM), indicating that the position of substitution at the quinoline ring is crucial. For 3'-COMe derivatives, the antiproliferative activity of 8-OH (11, 1.20 microM) is more potent than its 8-OMe counterpart (10, 8.91 microM), indicating that a H-bonding donating substituent is more favorable than that of a H-bonding accepting group. Comparison of 8-OH derivatives, the antiproliferative effect of COMe (11) is more potent than its oxime derivative (15a, 2.88 microM), which in turn is more potent than the methyloxime counterpart (15b, 5.50 microM). Compound 11 is especially active against the growth of certain solid cancer cells such as HCT-116 (colon cancer), MCF7, and MDA-MB-435 (breast cancer) with GI50 values of 0.07, <0.01, and <0.01 microM, respectively. Flow cytometric analyses revealed that growth inhibition by 11 and 15a was due to accumulation in S-phase. This result is interesting because 2-phenylquinolone derivatives have been reported to be antimitotic agents which induced cell cycle arrest in G2/M phase.