The Sr(4-x)Ca(x)Mn2CoO9 compounds are geometrically frustrated transition metal (TM) oxide, which present a variety of interrelated magnetic behavior. The (Mn,Co) TM form a triangular lattice of spin-chain with one CoO6 trigonal prism alternating with two MnO6 octahedra along the chain . The magnetic, specific heat and powder neutron diffraction measurements show that these compounds evolve from single ion magnetism (SIM) behavior to a long range magnetic order (LRO) with Ca doping, with a persistent single chain magnetic (SCM) behavior. In addition we observed a magnetoelectric coupling (ME). The proposed INS investigation will enable us to understand the nature of magnetic ground state and details spin dynamics, which in turns will help us to understand the mechanism of ME coupling and the significant role of non-magnetic ions (Ca/Sr) on this complex magnetism.