We report two efficient materials for p-type dye-sensitized solar cells, namely S64 and S85. Novel p-type photosensitizers for NiO-based dye-sensitized solar cells are presented in this study. Two compounds comprising a diphenylamine donor appended to a 1,8-naphthalene imide chromophore are successfully synthesised and characterised using infrared, nuclear magnetic resonance and mass spectroscopy techniques. Furthermore, their electrochemical properties are investigated using absorption spectroscopy, emission spectroscopy and cyclic voltammetry. Carboxylic acid anchoring groups are added to the two naphthalene compounds, so that the dyes are adsorbed onto NiO electrode of the dyes. These new materials achieve excellent solubility in organic solvents with extended π-conjugation and long alkyl chains. These dyes show good efficiency in NiO-based p-type dye-sensitized solar cells. Additionally, their external quantum efficiency measurements show a reasonable efficiency in the visible region.