[en] The search for new room temperature magnetoelectric materials for future multifunctional device application is the motivation behind the preparation of polycrystalline Bi_2(1−x)Ho_2xFe_4(1−y)Co_4yO₉ (x = y = 0; x = 0, y = 0.02; x = 0.02, y = 0 and x = y = 0.02) ceramics. Along with substantial variation in antiferromagnetic transition (T _N) in substituted samples (BFCO2, BHFO2), the co-substituted sample (BHFCO2) shows an enhanced T _N at room temperature i.e. 288 K as compared to parent BFO (250 K). All the samples except BHFO2, depicts a clear irreversibility in ZFC-FCW for T < 360 K along with an opening in MH curves, thus indicating the onset of weak ferromagnetism associated with magnetic glassiness in the studied samples. The dielectric measurements reveal an unusual oppression/hump around T _N, thereby providing evidence of magnetodielectric (MD) coupling, without any possibility of magnetoresistance. Moreover, a dielectric crossover at T ∼ 200 K is seen for BHFO2 and BHFCO2 while the mechanism is explained using a mean-field approximation model, thus validating the presence of isolated defects due to Ho³⁺. Lastly, all the samples are subjected to MD study, where the co-substituted sample exhibited ∼ −0.4% (∼7.5 times) of MD% effect at 288 K as compared to BFO (∼ −0.06%). Confirmation to the MD coupling is further established from MD% versus T plot and MD% versus H plot where later is found to obey $\propto <!--\; ???\; -->{(H)}^m$ behavior, with ‘m’ value being comparable to exponent (1-p) of thermoremanent magnetization. (paper)