An electronic transition of the AlC2 radical (C-2 nu structure) has been observed using laser-induced fluorescence spectroscopy. The molecule was prepared in a supersonic expansion by ablation of an aluminum rod in the presence of acetylene gas. A spectrum was recorded in the 451-453 nm region and assigned to the (C) over tilde B-2(2)-(X) over tilde (2)A(1) system (T-0 = 22102.7 cm(-1)) based on a rotational analysis and agreement with calculated molecular parameters and excitation energies. Ab initio results obtained using couple cluster methods are in accord with previous theoretical work which concludes that ground-state AlC2 possesses a T-shaped C(2 nu)(2)A(1) geometry, with the linear (2)Sigma(+) AlCC isomer 0.70 eV higher in energy. A fit of the experimental spectrum yields rotational constants in the ground and electronically excited states that are in reasonable agreement with the calculated values: A '' = 1.7093(107), B '' = 0.4052(50), C '' = 0.3228(49) cm(-1) for the (X) over tilde (2)A(1) state, and A' = 1.5621(137), B' = 0.4028(46), C' = 0.3201(54) cm(-1) for (C) over tilde B-2(2). Variation in individual fluorescence lifetimes suggests that the emitting (C) over tilde B-2(2) state undergoes rovibronic mixing with lower lying electronic states.