We have synthesized three Y bMn 6 Sn 6−x In x representatives (x=0.45, 0.80, 1.20), the first pseudo-ternary RMn 6 Sn 6−x X′ x compounds involving a divalent R metal. The crystal structure is found to evolve with the In concentration without modification of the Yb valency: Y bMn 6 Sn 5.55 In 0.45 is isotypic with HoFe 6 Sn 6 (Immm) while Y bMn 6 Sn 5.20 In 0.80 and Y bMn 6 Sn 4.80 In 1.20 crystallize in the TbFe 6 Sn 6 -type (Cmcm). The In content is also determining as regards the magnetic and magnetocaloric properties: Y bMn 6 Sn 5.55 In 0.45 (TC=216K) almost behaves like a simple ferromagnet while Y bMn 6 Sn 5.20 In 0.80 and Y bMn 6 Sn 4.80 In 1.20 also order ferromagnetically but at significantly lower temperatures (TC=154K and 129 K, respectively) and are further characterized by the interference of low temperature antiferromagnetic interactions. The results are discussed and compared to previously published data.