We propose a method to suppress the chemical reactions between ultracold bosonic ground-state 23 Na 87 Rb molecules based on optical shielding. By applying a laser with a frequency blue-detuned from the transition between the lowest rovibrational level of the electronic ground state X 1 Σ þ ðv X ¼ 0; j X ¼ 0Þ, and the long-lived excited level b 3 Π 0 ðv b ¼ 0; j b ¼ 1Þ, the long-range dipole-dipole interaction between the colliding molecules can be engineered, leading to a dramatic suppression of reactive and photoinduced inelastic collisions, for both linear and circular laser polarizations. We demonstrate that the spontaneous emission from b 3 Π 0 ðv b ¼ 0; j b ¼ 1Þ does not deteriorate the shielding process. This opens the possibility for a strong increase of the lifetime of cold molecule traps and for an efficient evaporative cooling. We also anticipate that the proposed mechanism is valid for alkali-metal diatomics with sufficiently large dipoledipole interactions.