The reaction of dimethyl- or diethylzinc with N,N,N-trimethylethylene- or propylenediamine gave a series of crystalline alkyl(dialkylamido)zinc compounds for which X-ray single-crystal structures have been determined. The four title compounds consist of dimeric molecular units, [RZnNMe(CH2)(n)NMe2](2). The same reactions in the presence of traces of moisture produced two different novel compounds whose crystal structures contain hexameric [R4Zn6O2(MeN(CH2)(n)NMe2)(4)] zinc units. Crystal data: MeZnNMe(CH2)(3)NMe2 (1), orthorhombic, Pbca, a = 14.578(2) Angstrom, b = 17.328(3) Angstrom, c = 15.765(3) Angstrom, beta = 90 degrees, Z = 8, R-W = 0.1095; EtZn Me(CH2)(3)NMe2 (2), orthorhombic, Pbca, a = 17.080(1) Angstrom, b = 16.062(1) Angstrom, c = 17.242(1) Angstrom, beta = 90 degrees, Z = 8, R-W = 0.0878; MeZnNMe(CH2)(2)NMe2 (4), triclinic, P (1) over bar a = 7.305(1) Angstrom b = 10.185(1) Angstrom, c = 12.307(1) Angstrom, alpha = 82.94(1)degrees, beta = 88.31(1)degrees, gamma = 80.69(1)degrees, Z = 2, R-W = 0.1089; EtZnNMe(CH2)(2)NMe2 (5), triclinic, P (1) over bar, a = 7.419(6) Angstrom, b = 8.317(6) Angstrom, c = 8.888(6)Angstrom, alpha = 85.13(5)degrees, beta = 105.59(6)degrees, gamma = 111.47(6)degrees, Z = 1, R-W = 0.0841; Me4Zn6O2[MeN(CH2)(3)NMe2](4) (6), monoclinic, P21/n, a = 18.485(7) Angstrom, b = 12.585(4) Angstrom, c = 19.756(5) Angstrom, alpha = 90 degrees, beta = 110.92(2)degrees, gamma = 90 degrees, Z = 4, R-W = 0.1234; Et4Zn6O2[MeN(CH2)(2)NMe2](4) (7), monoclinic, I2, a = 11.387(1) Angstrom, b = 15.547(1) Angstrom, c = 12.320(1) Angstrom, beta = 90 degrees, Z = 2, R-W = 0.0906.