A new organic donor-π-acceptor sensitizer MKA253 has been applied for highly efficient solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2,7,7-tetrakis (N,N-di-p-methoxyphenyl-amine ) 9,9-spirobifuorene (Spiro-OMeTAD) as the hole transport material (HTM), excellent power conversion efficiency of 6.1% was recorded together with a high short-circuit current of 12.4 mA/cm2 under standard AM 1.5G illumination (100 mW cm-2). Different combinations of dyes and HTMs have also been investigated in ssDSSC device. The results showed that, small molecule HTM based-devices suffer from comparably high electron recombination losses, thus causing low open-circuit voltage. In addition, photo-induced absorption (PIA) spectroscopy showed that the small-molecule HTMs lead to more efficient dye regeneration in comparison with Spiro-OMeTAD, despite a lower thermodynamic driving force. The results of this study also show that optimized energy levels for the dye/HTMs could be a vital factor for highly efficient ssDSSCs.