In the title mononuclear Cu(I) complex, [Cu(C(18)H(15)P)(C(41)H(39)P(3))]BF(4), the cation has a basic rigid core structure reminiscent of the framework of diamond. The metal atom is coordinated by four P atoms in a distorted tetra-hedral geometry, the distortion arising from the steric hindrance of the phenyl groups. The anion is disordered over two positions, with an occupancy ratio of 0.524 (17):0.476 (17). The cations and anions are closely packed in the crystal and are in h.c.p. arrangements.