Utilization of small-molecule based organic photovoltaic (OPV) devices has received strong attention due to their easy preparation, purification, and batch-to-batch resemblance in properties. In this work, a series of simple benzothiadiazole and triphenylamine-containing molecules were synthesized, and their application to organic photovoltaic devices was investigated. The absorption spectra demonstrated that the absorption wavelength of the small molecules could be tuned dramatically by extension of molecular structure from donor-acceptor-acceptor (D-A-A’) to A’-A-D-D-A-A’ sequences. Due to the intramolecular energy transfer from the acceptor to donor and vice versa in D-A-A’ structures in prepared molecules, the maximum emission wavelengths were red-shifted gradually with the increase of chain length. Bulk heterojunction (BHJ) type solar cell devices were fabricated by using the small molecules as donors and (6,6)-phenyl C61-butyric acid methyl ester (PC61BM) as acceptor (2:1), gave maximal open circuit voltage of the photovoltaic cells of 0.59 V and the power conversion efficiencies of the devices were measured 0.83% under AM 1.5G irradiation (100 mWcm-2).