Structures and Luminescence Properties of Two Zn(II) Coordination Polymers Based on Rigid‐Flexible Coligands

Zinc‐based fluorescent coordination polymers (Zn‐CPs) have demonstrated significant advances in multi‐applications, yet the impact of auxiliary ligand topology on framework assembly and photophysical properties in mixed‐ligand Zn‐CPs remains underexplored. This study presents the rational design and synthesis of two Zn(II) coordination polymers, [Zn 3 (ITA) 2 (VitPP) 2 ] n ( 1 ) and [Zn 2 (ITA) 2 (PZ)(H 2 O) 4 ] n ( 2 ), constructed from flexible itaconic acid (ITA) with auxiliary rigid ligands of nicotinic acid (VitPP) or pyrazine (PZ). Single‐crystal X‐ray diffraction reveals distinct 2D architectures: 1 contains μ 4 ‐ITA 2− /μ 3 ‐VitPP − bridged trinuclear [Zn 3 ] cluster nodes, while 2 shows μ 2 ‐PZ‐linked 1D [Zn(ITA)] chain units. Thermogravimetric analyses highlight exceptional thermal stability for 1 , in sharp contrast to the stepwise degradation of 2 involving sequential loss of coordinated H 2 O and PZ. Both CPs exhibit solid‐state fluorescence; 1 emits at 374 nm (excitation at 330 nm) due to trinuclear cluster‐induced rigidification and minimal π ‐stacking. Conversely, 2 shows a ≈50 nm redshifted emission ( λ em,max = 424 nm, λ ex,max = 374 nm) arising from extended π ‐conjugation in PZ.