The anions of CsC2 and CsC4 produced by sputtering a graphite surface with Cs+ were mass-selected and trapped in neon matrixes at 6 K. The electronic absorption spectra of CsC2 and CsC4, obtained by photodetachment of electrons from the anions, were measured subsequently and reveal strong absorptions in the visible range, which resemble the known band systems of C-2(-) and C-4(-), respectively. The origin band of CsC2 (500.4 nm) and CsC4 (442.6 nm) is shifted by similar to 1100 or by similar to 700 cm(-1) to the blue from the position of the 0(0)(0) band of C-2(-) or C-4(-). The observed system of CsC2 is assigned to the B-2(2)-X (2)A(1) electronic transition of the T-shaped form. The CsC4 spectrum is consistent with a C-4(-) chain slightly perturbed by the Cs atom. The oscillator strength of the observed electronic transition of CsC2 and CsC4 is an order of magnitude larger than for the respective carbon anions. CsC2- has a weak electronic transition, assigned to B-1(2)-X (1)A(1) in the C-2v form, with origin band at 516.5 nm.