The combination of Ni2+, dipropylenetriamine (dipn), and [Cr(CN)(6)](3-) affords the cyanide-bridged bimetallic assembly, [Ni(dipn)](3)[Cr(CN)(6)](2) center dot 3H(2)O (1). This compound crystallizes in cubic space group Pa3, with a = b = c = 20.9742 - (7)A and Z = 8. A three-dimensional network is constructed on the basis of a Cr8Ni12 cubane unit formed by an alternate array of [Cr(CN)(6)](3-) and [Ni(dipn)](2+) units through Cr-CN-Ni-NC-Cr edges. Cryomagnetic studies reveal a ferromagnetic interaction between Cr-III and Ni-II ions and a long-range ferromagnetic ordering below 42 K with very small coercive field. To the best of our knowledge, this compound is the first "complete ferromagnet" providing three-dimensional ferromagnetic interaction through a three-dimensional bridging structure that is based on a cubic unit among general metal-oxide and molecule-based magnets. Magnetooptical studies demonstrate a strong correlation between magnetic and optical properties.