A new compound 1,1'-bis(3-pyridyl)-propylene(3,7-diformyl-N-ethylphenothiazinyl)ketone (C30H23N3O2S, M-r = 489.4) has been synthesized, and its crystal structure was determined' by single-crystal X-ray diffraction method. The crystal is of orthorhombic, space group Ima2 with a = 27.491(5), b = 11.942(2), c = 7.389(2) angstrom, V = 2425.8(7) angstrom(3), Z = 8, D-c = 1.340 g/cm(3), mu = 0.167 mm(-1), F(000) = 1024, the final R = 0.0363 and wR = 0.0869 for 2054 unique reflections with R-int = 0.0254. The structural determination shows that the molecule assumes a butterfly configuration with nearly planar wings. In addition, the electrochemical study indicates that there is a high electronic delocalization in the molecule.