A series of oxides LnBaCuCoO5 (Ln=Pr, Nd, Sm, Dy, Gd, Ho and Er) have been synthesized by ceramic method. The oxides crystallize in a tetragonal structure, isostructural to YBaCuCoO5. All the oxides in the series are semiconducting. IR spectra of these oxides show distinct absorption bands at 630 cm−1, 550 cm−1 and 330 cm−1 which are assigned toE,A2 andA1 modes respectively. Doping of holes in these oxides, by calcium substitution in Er1−xCaxBaCuCoO5−x (up tox ⋍ 0·3) was done but, these oxides did not show metallic behaviour.