Probabilities of spontaneous rovibronic transitions I 1∏g-,v′J′, J 1Δg-, v′, J′ → C 1∏u±, v″, J″ of the D2 molecule (for vibrational and rotational quantum numbers v′ = v″ = 0-3 and J′ = 1-9, J″ = J′ ± 1) have been obtained for the first time. They were determined using (1) the previously proposed nonadiabatic model, which takes into account the electron-rotational interaction of the upper levels; (2) the coefficients of expansion of wave functions of perturbed states in the Born-Oppenheimer basis, which were found from the experimental data on rovibronic terms; and (3) semiempirical ab initio data on electronic transition dipole moments of the 3dπ 1∏g → 2pπ1u and 3dδ1Δg → 2pπ1∏ u transitions. The dependences of the transition probabilities on J′ for the same bands of both hydrogen isotopomers H2 and D2 were found to be identical. They represent monotone functions for R and P branches and functions with a maximum (minimum) for Q branches. The ratios of transition probabilities of different isotopomers for dif