The diazonium salt derived from 4-amino-N,1,3-trimethyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-1Hpyrazole-5-carboxamide ( 14) was reacted with a mixture of CuSO 4 and NaCl, with ascorbic acid as an initiator to afford the planar derivative 4, 6-dihydro-1,4,6,8-tetramethyl-3-phenyldipyrazolo[3,4-b:4',3'-d]pyridin-5(3H)one ( 16) and its unexpected isomer 4,6-dihydro-3,4,6,8-tetramethyl-1-phenyldipyrazolo[4,3-b:4',3'-d]pyridin-5(1H)-one ( 17), as well as the epimers (3S,4S)-(or (3S,4R)-) and (3S,4R)-(or (3S,4S)-) 4-chloro-2,4-dihydro-1',3',5,5'-tetramethyl-2-phenylspiro[pyrazole-3,4'(1'H)-pyrrolo[3,4-c]pyrazol]-6'(5'H)-one (18a and b, respectively). Epimers 18a and b were converted under basic conditions to 4'-chloro-N,1,3,3'-tetramethyl-1'-phenyl-[4,5'-bi-1H-pyrazole]-5-carboxamide ( 19). The structures of isomers 16 and 17 determined by single-crystal Xray analysis are also reported. Linear dichroism (LD) measurements for the above isomers suggest that 17 intercalates into DNA, and 17 exhibited antiproliferation activity against human NCI-H460 pulmonary carcinoma cells.