<p>Tuning the optoelectronic response of π-conjugated building blocks is central to the design of next generation organic optoelectronic and nonlinear optical (NLO) materials, yet achieving robust and predictable modulation beyond conventional donor–acceptor substitution remains challenging. Metal nanoclusters offer an alternative route as electronically active modifiers; however, the structure–property relationships are often elusive, and tubular motifs are not typically preferred for small pure Ag_n​ clusters (up to Ag₂₀​). Here, density-functional approaches combined with NEGF-based transport simulations are used to assess whether a doubly doped, tube-like W₂@Ag₁₇​ nanocluster can act as an efficient modulating agent for benzo[1,2-b:4,5-b′]dithiophene (BDT) derivatives. We identify a triple-ring cylindrical lowest-energy structure among the explored isomers for W₂@Ag₁₇​, in which a vertical W₂​ dimer is encapsulated by an Ag₁₇ antiprismatic framework, and show that W₂​ doping substantially enhances cluster stability. Adsorption of BDT derivatives on this surface is thermodynamically favorable and induces pronounced electronic and optical reconfiguration, including a reduced frontier orbital gap and red-shifted absorption. Importantly, the NLO response of the BDT derivatives is strongly amplified upon cluster assembly. Transport analyses further reveal that W₂@Ag₁₇​ functionalization introduces additional transmission channels near the Fermi level and enhances conductivity in a morphology-dependent manner, with a more notable improvement for the BDT-B junction than for BDT-A. Overall, the results suggest tube-like W₂@Ag₁₇​ as a viable nanocluster modifier to concurrently tune optical nonlinearity and charge transport in π-conjugated BDT systems.</p>