We designed our synthetic pathway so that the parent phases Sr2MnO2Cu1.5Ch2 (Ch = S, Se) are first subject to Li-Cu exchange, followed by Li/Cu deintercalation and Cu dissolution using an oxidising agent highly chemoselective toward Cu cation complexation . The final product reveals unprecedented intergrowth structures consisting of 2D arrays of chalcogen dimers. for its structure parameters), d 2D kernel plot representing occurrence of (Sx, Sy) values refined for sliding of each Sr2MnO2S2 layer (See also Fig. ).