The electronic absorption spectra of linear C6H+ and C8H+ were recorded in 6 K neon matrixes following mass selective deposition. The (1) (3)Sigma(-)-X (3)Sigma(-) electronic transition is identified with the origin band at 515.8 and 628.4 nm for l-C6H+ and l-C8H+, respectively. One strong (near 267 nm) and several weaker electronic transitions of l-C8H+ have also been observed in the UV. The results of ab initio calculations carried out for linear and cyclic C6H+ are consistent with the assignment.