Recently, we have successfully realized the synthesis of one-dimensional (1D) van der Waals heterostructures, with single-walled carbon nanotube (SWCNT) as a template. A typical 1D heterostrucure is composed of coaxial SWCNT, boron nitride nanotube (BNNT), and molybdenum disulfide nanotube (MoS2NT), which should be a promising building block of the electronics and optoelectronic devices. At the same time, the enhanced thermal conductance of the thin film made of BNNTs over SWCNTs is very promising for macroscopic applications of heterostructures. Because BNNT coating over SWCNT film will not influence the transparency in the visible range, those films are immediately applicable for a saturable absorber in mode-lock fiber lasers or a pellicle membrane in extreme ultraviolet (EUV) lithography. The mechanism of the enhancement of thermal conductance from a film of SWCNTs will be discussed in detail. On the other hand, full heterostructure film composed of SWCNT-BNNT-MoS2NT is expected to be employed as active layer, hole-transport-layer, or transparent electrode of next generation solar cells. The preliminary application in the perovskite solar cells shows considerable advantage over SWCNT films. The SWCNT-based transparent electrode is practically useful in perovskite-Si tandem solar cells. The current tandem solar cells with total power conversion efficiency (PCE) more than 27 % will be discussed.