The family of human muscarinic acetylcholine receptors (MRs) is characterized by a high sequence homology among the five subtypes (MR-MR), being the reason for a lack of subtype selective MR ligands. In continuation of our work on dualsteric dibenzodiazepinone-type MR antagonists, a series of MR ligands containing a dibenzodiazepinone pharmacophore linked to small basic peptides was synthesized (64 compounds). The linker moiety was varied with respect to length, number of basic nitrogens (0-2) and flexibility. Besides proteinogenic basic amino acids (Lys, Arg), shorter homologues of Lys and Arg, containing three and two methylene groups, respectively, as well as D-configured amino acids were incorporated. The type of linker had a marked impact on MR affinity and also effected MR selectivity. In contrast, the structure of the basic peptide rather determined MR selectivity than MR affinity. For example, the most MR selective compound (UR-CG188, 89) with picomolar MR affinity (pK 9.60), exhibited a higher MR selectivity (ratio of K MR/MR/MR/MR/MR: 110:1:5200:55:2300) compared to the vast majority of reported MR preferring MR ligands. For selected ligands, MR antagonism was confirmed in a MR miniG protein recruitment assay.