Employing an uninvestigated eight N-donor bitriazole ligand, 5′-(pyrazin-2-yl)-2H,4′H-3,3′-bi(1,2,4-triazole) (H₂pzbtz), five complexes, {[Zn₂(pzbtz)(SO₄)(H₂O)₂]·2H₂O}_n (1), {[Cd(pzbtz)]·3H₂O}_n (2), [Zn₃(Hpzbtz)₂(SO₄)₂(H₂O)₆] (3), [Co(Hpzbtz)₂(H₂O)₂] (4) and {[Co₂(pzbtz)₂(H₂O)₂]·4H₂O}_n (5), have been solvothermally synthesised by altering the reaction solvents and temperatures. Complex 1 shows a three-dimensional (3D) framework with a very rare (3,5)-connected fsc-3,5-Cmce-2 topology. Complex 2 exhibits a (4,4)-connected 3D pts framework with 1D channels. Complexes 3 and 4 are discrete trinuclear and mononuclear molecules, respectively. Complex 5 presents a chiral 3D framework based on a novel trinuclear Co₃(tr)₄ cluster and features an unusual six-connected lcy topology. In the five complexes, H₂pzbtz show a very variety of geometrical configurations and coordination modes. Due to the planarity of H₂pzbtz, complexes 1–3 display strong photoluminescence; in particular, 1 features highly selective luminescent sensing for the Cu²⁺ ion and nitrobenzene molecule. In addition, 2 shows highly selective adsorption for CO₂ over CH₄, and 5 exhibits antiferromagnetic exchange interactions among the Co²⁺ ions.