Calculations were performed for the first time for the equation of state, the energetic band structure, and the densities of states for a novel allotropic modification of carbon that was synthesized previously and established recently to consist of the simple cubic lattice built from molecules C24 (SCF-C24) copolymerized by square faces, known previously as "cubic graphite." Volume dependence of total energy was shown to have the equilibrium minimum under an inter-carbon distance aCC = 0.1550 nm, intermediate between diamond (0.1544 nm) and graphite (0.1421 nm). Band structure consisted of five bands with semiconducting band gap ∼ 1.9eV. On the density-of-state curve the sharp peaks are pronounced as a peculiar feature of zero-dimensional fullerene molecules. In conclusion the SCF-C24 was shown to be the diamond-like, direct-band molecular semiconductor combining a non-polarizability and porosity with its mechanical strength (bulk modulus B = 308 GPa), chemical inertness, thermal stability, high thermal conductance, and compatibility in lattice parameter (0.5933 nm) with number of semiconductors. All of these point to the SCF-C24 as a high promising low-dielectric material (ϵ<5.7) for fast interconnectors and integrated circuits substrates in future nanoelectronics.