Three s-triazine derivatives have been synthesized and their structures been de-termined. These are Compound I: 2,4-Dimethyl-6-(p-N, N-dimethylaminostyryl)-s-triazine (ab-breviated to NMe-1), Compound II: 2, 4-Dimethyl-6-(p-N, N-diethylaminostyryl)-s-triazine (to NEt-1), and Compound III: 2-Methyl-4, 6-bis(p-N, N-dimethylaminostyryl)-s-triazine (NMe-2). NMe-1 and NEt-1 molecules belong to the D-π-A type with a one-dimensional charge-transfer character. NMe-1 crystallize to centrosymmetric 1P space group, while NEt-1 to non-centro- sym- metric polar Cc space group with all of the molecular charge-transfer axes taking the same orientation. Under the irradiation of 1064 nm fundamental laser, NEt-1 powder crystals radiate a 2-order harmonic light with an intensity 46.8 times that of urea. The Λ typed NMe-2 molecule, which has a two-dimensional charge-transfer character, crystallize to polar P21 space group. Its powder crystals exhibit a 2-order harmonic intensity 46.2 times that of urea. The quantum chemical calculations and tensor analyses have been carried out to reveal the dependence of the macro 2-order nonlinear optical (NLO) efficiency on the micro 2-order NLO coefficients (β) and on the crystalline packing styles.