Ce2Rh3Al9 has been known as a nonmagnetic heavy-fermion with a temperature dependence of a specific-heat characteristic for the non-Fermi liquids. We present the low-temperature specific heat, AC magnetic susceptibility and electrical resistivity, which display an anomaly at about 20K. The low-temperature specific-heat data are well described by the S=12 Kondo model. We found also that the low-temperature power-law behavior in the specific-heat and AC susceptibility data can be attributed to the 4f Ce electrons, whereas, the spin fluctuations due to 4d Rh electrons become pronounced at higher temperatures T>10K. We also investigated Ce2Rh2CoAl9. The specific heat clearly shows the magnetic ground state of Ce2Rh2CoAl9. The specific heat jump in ΔC at the temperature of magnetic ordering is strongly reduced by Kondo effect. In our linearized muffin-tin orbitals (LMTO) and full potential local orbital (FPLO) calculations both the compounds are nonmagnetic. The stability of an antiferromagnetic ground state in Ce2Rh2CoAl9 is discussed in the Kondo-lattice limit within the model proposed by Doradziński and Spałek.