A dipolar two-dimensional multifunctional (D-pi)(3)-A dye molecule, 3,4,6-tris(4-(N-methyl-N-hexaclecylamino)-styryl)pyrylium tetrafluoroborate (P-3) was synthesized. The dye molecule was successfully transferred onto an ITO electrode or quartz by the Langmuir-Blodgett (LB) technique. The second-harmonic generation (SHG) and photoelectric conversion (PEC) properties of the "molecular umbrella" monolayers were studied under 10 and 40 mN m(-1) surface pressure. The different tilt angle of the "molecular umbrella" results in the difference of SHG and PEC properties; For comparison, dipolar one-dimensional molecule 2,6-dimethyl-4-(4-(N-methyl-N-hexadecylamino)styryl)pyrylium tetrafluoroborate (P-1) was also investigated. The experimental results show that the SHG and PEC properties of the dipolar two-dimensional molecule (P-3) are better than those of the dipolar one-dimensional molecule (PI). For example, under favorable conditions (-100 mV, dissolved Oz, 2 mM MV2+, and 4 mM EU3+), the quantum yields for P-3 and P-1 monolayers (deposited under 40 mN m(-1)) are 1.21 and 0.42%, respectively.