The infrared spectra over the range 4000–50 cm−1 of three copper basic sulfates, viz. Cu4(OH)6SO4, Cu4(OH)4OSO4, Cu3(OH)4SO4 along with site group and factor group analysis for Cu4(OH)6SO4 are reported for the first time. The observed absorption frequencies associated with OH and SO4 activities show distinct individual structural features.Three distinct types of OH groups are present in Cu4(OH)6SO4 and Cu4(OH)4OSO4 but only two types are evident in Cu3(OH)4SO4. The two OH groups involved in the dehydroxylation reaction to give the oxycompound Cu4(OH)4OSO4 are tentatively identified. The multiple frequencies involving Cu—O—H bending modes further reflect the varying degrees of H-bonding and OH coupling in Cu(OH)4O2 and Cu(OH)5O entities.The SO4 internal optic modes' multiplet structure and frequencies in the basic sulfates illustrate the different extent of dipolar coupling effects (OH and Cu) with respect to specific modes relative to Li2SO4 with same site symmetry. The SO4 external optic modes relative to Li2SO4 are barely affected by neighboring OH groups.The Cu—O mode frequencies show parallel behavior with minor interaction effects in all compounds.