Fifteen cis-dichloroplatinum complexes (5a–5o) were synthesized by treatment of 1-(2- aminophenyl)-1, 2, 3, 4-THIQs (4a–4o) with K2PtCl4. The antitumor activity of these compounds was examined against four different human tumor cell lines. Their structure– activity relationships for antitumor activity are reported. All of these compounds exhibited activity against MCF-7 cell line and showed good activity against WiDr cell line except 5c ...