Trinuclear chiral (LH)(2)L2Cu3 (LH = 1,3-diamino-2-propanol, bdapH) assemblies linked by octacyanidometalate(IV) form isostructural one-dimensional (1D) chains consisting of right- and left-handed helixes arranged in an alternate manner: [(bdapH)(2)(bdap)(2)Cu(II)3][M-IV(CN)(8)]center dot H2O (M = Mo 1, W 2). Each chain displays helicity with a long pitch around 17.2 angstrom. The direction of the helix rotation is strictly connected with the conformation of the (LH)(2)L2Cu3 unit. Right-handed helixes are based on Delta-S,S-(LH)(2)L2Cu3, whereas left-handed ones contain Delta-R,R-(LH)(2)L2Cu3 units. Magnetic studies reveal antiferromagnetic interactions through alkoxo-bridges inside trinuclear Cu(II) nodes leading to an S-T = 1/2 ground state for both assemblies.