The hydrothermal reactions of CuX2 or CuX with phen (1,10-phenanthroline) have resulted in the syntheses of eight compounds 1–8. In these, 1∶1 adducts of CuX/phen are reported: ionic [Cu(phen)2][CuX2] (X = Cl 1, Br 2) and dimer [Cu2I2(phen)] 3; the trinuclear clusters [Cu3X3(phen)2] (X = Br 5, I 7) were first prepared and the structures can be best described as 1∶1 adducts of dimers and CuX; the chain compounds 6 and 8 belong to the same series with the formula [CuX2L] (L = organic ligand), but the chain arrangement is different; the structure of 4 is yet being refined. Compounds 1–8 have a high thermal stability. The third-order nonlinear optical properties of compounds 5, 6 and 8 were investigated and all exhibit a reverse saturable absorption (α2 > 0) and self-defocusing performance (n2 < 0).