Two isostructural adducts CHI3 center dot(S8)(3) (1) and AsI3 center dot(S-8)(3) (2) are synthesized by a simple solution method. Both of them crystallize in noncentrosymmetric R3m, featuring van der Waals interaction linked CHI3 tetrahedra or SbI3 trigonal pyramids with crown-like S-8 molecules. Both 1 and 2 show strong SHG responses and phase matchability under either 1.064 or 2.1 mu m. The results of DFT calculations indicate that the electron transfer happens from S-3p to I-5p orbitals, and both of them demonstrate indirect band gaps. The NLO effects of 1 and 2 are almost fully contributed from the CHI3 or AsI3 units. Compared with AgGaS2, their powder laser damage thresholds are ca. 15 and 51 times higher.