The effect of transition metal ions(M~(2+)=Mn~(2+),Ni~(2+),Co~(2+),Cu~(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I~-/I_3~-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn~(2+),Ni~(2+),Co~(2+) (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu~(2+)decreased the power conversion efficiency of PANI CE(PANI-Cu~(2+) η = 1.41%). The electrical properties of the PANI, PANI-Ni~(2+), PANI-Co~(2+),PANI-Mn~(2+) and PANI-Cu~(2+) were studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M~(2+)=Mn~(2+),Ni~(2+),Co~(2+),Cu~(2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs. The effect of transition metal ions (M ~ (2 +) = Mn ~ (2 +), Ni 2+, Co 2+, Cu 2+) on the chemical synthesis of polyaniline ) used as a platinum-free counter electrode (CE) in dye-sensitized solar cells (DSSCs) was investigated. PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide / triiodide (I ~ - / I_3 ~ -) redox couples. The power conversion efficiency (η) of PANI CEs doped with Mn ~ (2+ Doping with Cu ~ (2+), Ni ~ (2 +) and Co ~ (2+) (4.41%, 2.36% and 2.10% respectively) were higher than 1.94% The electrical properties of the PANI, PANI-Ni 2+, PANI-Co 2+, PANI-Co 2+, and PANI- Mn 2+ and PANI-Cu 2+ were studied by cyclic voltammetry (CV), impedance (EIS), and Tafel polarization cur ve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions (M ~ (2 +) = Mn ~ (2+), Ni 2+, Co 2+, Cu ~ 2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.