Two novel metal–organic frameworks (MOFs) based on different tetradentate in situ ligands, Cu^I₃(L¹)₂(L²)[PMo^VI₈V^V₄O₄₀(V^IVO)₂]·2H₂O (1) and [Cu^I₂Cl₂(L³)] (2) (L¹ = 1,4-bis(imidazol-1-ylmethyl)benzene, L² = 1,2,4,5-tetra(4-pyridyl)-benzene L³ = a-1-hydroxy-e,e,e,e-1,2,4,5-tetra(4-pyridyl)cyclohexane) have been rationally hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, TG analyses, and single-crystal X-ray diffraction, respectively. Here, compound 1 represents the first example that dehydrogenative coupling has been employed to yield a novel tetradentate coplanar dye molecule in POM-based MOFs. It also exhibits unique 3D MOFs with two topologies (4²8⁴)(4²8³10¹)(8⁶)₂ and (4³8³)(4²8⁴)(4⁴6²8⁹)(4¹⁰6¹8³) due to different definitions of nodes. Compound 2 shows a two-fold diagonal/diagonal inclined interpenetration based on Cu^I ions and in situ synthesized ligands L³. Interestingly, reaction conditions play important roles in the domination of in situ ligands (L² and L³) from the same precursor bpp (bpp = 1,3-bis(4-pyridyl)propane). Additionally, electrochemical and photocatalysis properties of compound 1 have also been minutely investigated.