The electronic absorption spectrum of the (0,2), (1,3), and (6,9) bands of the B(4)Sigma(u)(-)-X(4)Sigma(g)(-) system of C-2(+) was obtained using the velocity modulation technique in conjunction with heterodyne detection. The rotationally resolved spectrum shows perturbations, which are attributed to the 2(2)Pi(u) state. The mixing between the B(4)Sigma(u)(-) state and the 2(2)Pi(u) state for nearly degenerate levels generated enough intensity borrowing to observe twenty 2(2)Pi(u)<--X(4)Sigma(g)(-) forbidden transitions. The parameters of a model Hamiltonian were fit to the bands and their corresponding forbidden transitions. Line position measurements, line strength factors, and expectation values for the orbital angular momentum for the forbidden transitions are reported. Molecular parameters from the global fit of each band, including their corresponding forbidden transitions, are reported. (C) 2004 American Institute of Physics.