A small organic sensitizer, the polyene-diphenylaniline dye D5, was compared with the standard sensitizer N719 (Ru(dcbpy)2(NCS)2) in a dye-sensitized solar cell investigation. In solar cells with relatively thin layers of mesoporous TiO2 (< 3 μm) D5 outperformed N719 because of its high extinction coefficient. D5 showed also better performance than N719 in the case of sensitization of mesoporous ZnO. In solid-state solar cells, where the iodide/triiodide electrolyte was replaced by an amorphous hole conductor (spiro-OMeTAD), D5 gave promising preliminary results. The hole conductivity, observed in monolayers of D5 adsorbed at TiO2, may possibly lead to improved performance in such cells. © 2007 Elsevier B.V. All rights reserved.