A photosensitizer dye is provided. The photosensitizer dye contains a Ru complex represented by the following formula (1): ##STR00001## wherein Y.sub.1 and Y.sub.2 independently represent hydrogen atom (H), lithium (Li), sodium (Na) or tetra-alkyl ammonium groups (as represented by the following general formula (2)). ##STR00002## wherein A, B, C and D independently represents C.sub.mH.sub.2m+1 (m=1.about.6). Wherein X.sub.1 represents one of the following formulas (3).about.(8) and X.sub.2 represents H or a group the same as X.sub.1, ##STR00003##