An accurate potential curve for the bound and quasibound region of the B (1)Pi (u) state of Li-7(2) is produced by analyzing high resolution sub-Doppler B (1)Pi (u)<--X (1)Sigma (+)(g) excitation spectra in conjunction with lower resolution data of Hessel and Vidal [J. Chem. Phys. 70, 4439 (1979)] and of Russier [J. Mol. Spectrosc. 168, 39 (1994)]. The bound and quasibound part of the curve is generated by the direct fit of molecular energies to a numerical potential; the outermost (repulsive) part of the curve is calculated by an asymptotic method using Coulombic and exchange parameters determined from the 1 (1)Pi (g) and A (1)Sigma (+)(u) states of the lithium dimer. The full potential energy curve of the B (1)Pi (u) state reproduces all measured energies of f parity, and the widths of the predissociated lines, to within the experimental accuracy.