A 3d-4f coordination polymer {[CoEu2(INAIP)4(H2O)6]·2.5H2O}n (1) was obtained by hydrothermal assembly of Co(OAc)2·4H2O and Eu(NO3)3·6H2O with H2INAIP (5-(isonicotinamido)isophthalic acid). Complex 1 crystallizes in triclinic, space group Pi with a=1.00889(13) nm,b = 1.08234(14) nm,c=2.9795(4) nm, V=3.200(7) nm3,Z=1, C112H90Co2Eu4N16O57,Mr=3297.70,Dc=1.711 g·cm-3,μ=2.285 mm-1, F(000)=1636, Rint=0.025 8, R=0.049 2,wR=0.1263. Single-crystal X-ray diffraction analysis revealed that each INAIP2- ligand uses its two carboxyl groups to connect t...