We studied the energy transfer processes in the molecular array consisting of pyrene (Py), biphenyl (Ph-2 and bisphthalimidethiophene (ImT), (Py-Ph-2)(2)-ImT, during two-color two-laser flash photolysis (2-LFP). The first laser irradiation predominantly generates ImT in the lowest triplet excited state (ImT(T-1)) because of the efficient singlet energy transfer from Py in the lowest singlet excited state to ImT and, then, intersystem crossing of ImT. ImT(T-1) was excited to the higher triplet excited state (T.) with the second laser irradiation. Then, the triplet energy was rapidly transferred to Py via a two-step triplet energy transfer JET) process through Ph2. The efficient generation of Py(T-1) was suggested from the nanosecond -picosecond 2-LFP. The back-TET from Py(T-1) to ImT was observed for several tens of microseconds after the second laser irradiation. The estimated intramolecular TET rate from Py(T-1) to ImT was as slow as 3.1 x 10(4) s(-1). Hence, long-lived Py(TI) was selectively and efficiently produced during the 2-LFP.